Targeting dietary fat or glycemic load in the treatment of obesity and type 2 diabetes: a randomized controlled trial

Effect of Dietary Approaches on Glycemic Control in Patients with Type 2 Diabetes: A Systematic Review with Network Meta-Analysis of Randomized Trials

BACKGROUND

Dietary patterns play a critical role in diabetes management, while the best dietary pattern for Type 2 diabetes (T2DM) patients is still unclear. The aim of this network meta-analysis was to compare the impacts of various dietary approaches on the glycemic control of T2DM patients.

METHODS

Relevant studies were retrieved from PubMed, Embase, Web of Knowledge, Cochrane Central Register of Controlled Trials (CENTRAL), and other additional records (1949 to 31 July 2022). Eligible RCTs were those comparing different dietary approaches against each other or a control diet in individuals with T2DM for at least 6 months. We assessed the risk of bias of included studies with the Cochrane risk of bias tool and confidence of estimates with the Grading of Recommendations Assessment, Development, and Evaluation approach for network meta-analyses. In order to determine the pooled effect of each dietary approach relative to each other, we performed a network meta-analysis (NMA) for interventions for both HbA1c and fasting glucose, which enabled us to estimate the relative intervention effects by combing both direct and indirect trial evidence.

RESULTS

Forty-two RCTs comprising 4809 patients with T2DM were included in the NMA, comparing 10 dietary approaches (low-carbohydrate, moderate-carbohydrate, ketogenic, low-fat, high-protein, Mediterranean, Vegetarian/Vegan, low glycemic index, recommended, and control diets). In total, 83.3% of the studies were at a lower risk of bias or had some concerns. Findings of the NMA revealed that the ketogenic, low-carbohydrate, and low-fat diets were significantly effective in reducing HbA1c (viz., -0.73 (-1.19, -0.28), -0.69 (-1.32, -0.06), and -1.82 (-2.93, -0.71)), while moderate-carbohydrate, low glycemic index, Mediterranean, high-protein, and low-fat diets were significantly effective in reducing fasting glucose (viz., -1.30 (-1.92, -0.67), -1.26 (-2.26, -0.27), -0.95 (-1.51, -0.38), -0.89 (-1.60, -0.18) and -0.75 (-1.24, -0.27)) compared to a control diet. The clustered ranking plot for combined outcomes indicated the ketogenic, Mediterranean, moderate-carbohydrate, and low glycemic index diets had promising effects for controlling HbA1c and fasting glucose. The univariate meta-regressions showed that the mean reductions of HbA1c and fasting glucose were only significantly related to the mean weight change of the subjects.

CONCLUSIONS

For glycemic control in T2DM patients, the ketogenic diet, Mediterranean diet, moderate-carbohydrate diet, and low glycemic index diet were effective options. Although this study found the ketogenic diet superior, further high-quality and long-term studies are needed to strengthen its credibility.

Comparative efficacy of different eating patterns in the management of type 2 diabetes and prediabetes: An arm-based Bayesian network meta-analysis

AIMS/INTRODUCTION

Diet therapy is a vital approach to manage type 2 diabetes and prediabetes. However, the comparative efficacy of different eating patterns is not clear enough. We aimed to compare the efficacy of various eating patterns for glycemic control, anthropometrics, and serum lipid profiles in the management of type 2 diabetes and prediabetes.

MATERIALS AND METHODS

We conducted a network meta-analysis using arm-based Bayesian methods and random effect models, and drew the conclusions using the partially contextualized framework. We searched twelve databases and yielded 9,534 related references, where 107 studies were eligible, comprising 8,909 participants.

RESULTS

Eleven diets were evaluated for 14 outcomes. Caloric restriction was ranked as the best pattern for weight loss (SUCRA 86.8%) and waist circumference (82.2%), low-carbohydrate diets for body mass index (81.6%), and high-density lipoprotein (84.0%), and low-glycemic-index diets for total cholesterol (87.5%) and low-density lipoprotein (86.6%). Other interventions showed some superiorities, but were imprecise due to insufficient participants and needed further investigation. The attrition rates of interventions were similar. Meta-regression suggested that macronutrients, energy intake, and weight may modify outcomes differently. The evidence was of moderate-to-low quality, and 38.2% of the evidence items met the minimal clinically important differences.

CONCLUSIONS

The selection and development of dietary strategies for diabetic/prediabetic patients should depend on their holistic conditions, i.e., serum lipid profiles, glucometabolic patterns, weight, and blood pressure. It is recommended to identify the most critical and urgent metabolic indicator to control for one specific patient, and then choose the most appropriate eating pattern accordingly.

Low-carbohydrate versus balanced-carbohydrate diets for reducing weight and cardiovascular risk

BACKGROUND

Debates on effective and safe diets for managing obesity in adults are ongoing. Low-carbohydrate weight-reducing diets (also known as 'low-carb diets') continue to be widely promoted, marketed and commercialised as being more effective for weight loss, and healthier, than 'balanced'-carbohydrate weight-reducing diets.

OBJECTIVES

To compare the effects of low-carbohydrate weight-reducing diets to weight-reducing diets with balanced ranges of carbohydrates, in relation to changes in weight and cardiovascular risk, in overweight and obese adults without and with type 2 diabetes mellitus (T2DM).

SEARCH METHODS

We searched MEDLINE (PubMed), Embase (Ovid), the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science Core Collection (Clarivate Analytics), ClinicalTrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) up to 25 June 2021, and screened reference lists of included trials and relevant systematic reviews. Language or publication restrictions were not applied.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in adults (18 years+) who were overweight or living with obesity, without or with T2DM, and without or with cardiovascular conditions or risk factors. Trials had to compare low-carbohydrate weight-reducing diets to balanced-carbohydrate (45% to 65% of total energy (TE)) weight-reducing diets, have a weight-reducing phase of 2 weeks or longer and be explicitly implemented for the primary purpose of reducing weight, with or without advice to restrict energy intake.  DATA COLLECTION AND ANALYSIS: Two review authors independently screened titles and abstracts and full-text articles to determine eligibility; and independently extracted data, assessed risk of bias using RoB 2 and assessed the certainty of the evidence using GRADE. We stratified analyses by participants without and with T2DM, and by diets with weight-reducing phases only and those with weight-reducing phases followed by weight-maintenance phases. Primary outcomes were change in body weight (kg) and the number of participants per group with weight loss of at least 5%, assessed at short- (three months to < 12 months) and long-term (≥ 12 months) follow-up.

MAIN RESULTS

We included 61 parallel-arm RCTs that randomised 6925 participants to either low-carbohydrate or balanced-carbohydrate weight-reducing diets. All trials were conducted in high-income countries except for one in China. Most participants (n = 5118 randomised) did not have T2DM. Mean baseline weight across trials was 95 kg (range 66 to 132 kg). Participants with T2DM were older (mean 57 years, range 50 to 65) than those without T2DM (mean 45 years, range 22 to 62). Most trials included men and women (42/61; 3/19 men only; 16/19 women only), and people without baseline cardiovascular conditions, risk factors or events (36/61). Mean baseline diastolic blood pressure (DBP) and low-density lipoprotein (LDL) cholesterol across trials were within normal ranges. The longest weight-reducing phase of diets was two years in participants without and with T2DM. Evidence from studies with weight-reducing phases followed by weight-maintenance phases was limited. Most trials investigated low-carbohydrate diets (> 50 g to 150 g per day or < 45% of TE; n = 42), followed by very low (≤ 50 g per day or < 10% of TE; n = 14), and then incremental increases from very low to low (n = 5). The most common diets compared were low-carbohydrate, balanced-fat (20 to 35% of TE) and high-protein (> 20% of TE) treatment diets versus control diets balanced for the three macronutrients (24/61). In most trials (45/61) the energy prescription or approach used to restrict energy intake was similar in both groups. We assessed the overall risk of bias of outcomes across trials as predominantly high, mostly from bias due to missing outcome data. Using GRADE, we assessed the certainty of evidence as moderate to very low across outcomes.  Participants without and with T2DM lost weight when following weight-reducing phases of both diets at the short (range: 12.2 to 0.33 kg) and long term (range: 13.1 to 1.7 kg).  In overweight and obese participants without T2DM: low-carbohydrate weight-reducing diets compared to balanced-carbohydrate weight-reducing diets (weight-reducing phases only) probably result in little to no difference in change in body weight over three to 8.5 months (mean difference (MD) -1.07 kg, (95% confidence interval (CI) -1.55 to -0.59, I2 = 51%, 3286 participants, 37 RCTs, moderate-certainty evidence) and over one to two years (MD -0.93 kg, 95% CI -1.81 to -0.04, I2 = 40%, 1805 participants, 14 RCTs, moderate-certainty evidence); as well as change in DBP and LDL cholesterol over one to two years. The evidence is very uncertain about whether there is a difference in the number of participants per group with weight loss of at least 5% at one year (risk ratio (RR) 1.11, 95% CI 0.94 to 1.31, I2 = 17%, 137 participants, 2 RCTs, very low-certainty evidence).  In overweight and obese participants with T2DM: low-carbohydrate weight-reducing diets compared to balanced-carbohydrate weight-reducing diets (weight-reducing phases only) probably result in little to no difference in change in body weight over three to six months (MD -1.26 kg, 95% CI -2.44 to -0.09, I2 = 47%, 1114 participants, 14 RCTs, moderate-certainty evidence) and over one to two years (MD -0.33 kg, 95% CI -2.13 to 1.46, I2 = 10%, 813 participants, 7 RCTs, moderate-certainty evidence); as well in change in DBP, HbA1c and LDL cholesterol over 1 to 2 years. The evidence is very uncertain about whether there is a difference in the number of participants per group with weight loss of at least 5% at one to two years (RR 0.90, 95% CI 0.68 to 1.20, I2 = 0%, 106 participants, 2 RCTs, very low-certainty evidence).  Evidence on participant-reported adverse effects was limited, and we could not draw any conclusions about these.  AUTHORS' CONCLUSIONS: There is probably little to no difference in weight reduction and changes in cardiovascular risk factors up to two years' follow-up, when overweight and obese participants without and with T2DM are randomised to either low-carbohydrate or balanced-carbohydrate weight-reducing diets.

Low-Glycemic Index Diets as an Intervention in Metabolic Diseases: A Systematic Review and Meta-Analysis

We aimed to investigate the effects of a low-glycemic index (GI) diet on the body mass and blood glucose of patients with four common metabolic diseases by conducting a systematic review and meta-analysis of studies comparing a low-GI diet (LGID) and other types of diet. Search terms relating to population, intervention, comparator, outcomes, and study design were used to search three databases: PubMed, Embase, and the Cochrane Library. We identified 24 studies involving 2002 participants. Random-effects models were used for 16 studies in the meta-analysis and stratified analyses were performed according to the duration of the intervention. The systematic review showed that LGIDs slightly reduced body mass and body mass index (BMI) (p < 0.05). BMI improved more substantially after interventions of >24 weeks and there was no inter-study heterogeneity (I² = 0%, p = 0.48; mean difference (MD) = -2.02, 95% confidence interval (CI): -3.05, -0.98). Overall, an LGID had superior effects to a control diet on fasting blood glucose (FBG) and glycosylated hemoglobin. When the intervention exceeded 30 days, an LGID reduced FBG more substantially (MD = -0.34, 95% CI: -0.55, -0.12). Thus, for patients with metabolic diseases, an LGID is more effective at controlling body mass and blood glucose than a high-GI or other diet.

Effect of low glycaemic index or load dietary patterns on glycaemic control and cardiometabolic risk factors in diabetes: systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To inform the update of the European Association for the Study of Diabetes clinical practice guidelines for nutrition therapy.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase, and the Cochrane Library searched up to 13 May 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials of three or more weeks investigating the effect of diets with low glycaemic index (GI)/glycaemic load (GL) in diabetes.

OUTCOME AND MEASURES

The primary outcome was glycated haemoglobin (HbA1c). Secondary outcomes included other markers of glycaemic control (fasting glucose, fasting insulin); blood lipids (low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), non-HDL-C, apo B, triglycerides); adiposity (body weight, BMI (body mass index), waist circumference), blood pressure (systolic blood pressure (SBP) and diastolic blood pressure (DBP)), and inflammation (C reactive protein (CRP)).

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed risk of bias. Data were pooled by random effects models. GRADE (grading of recommendations assessment, development, and evaluation) was used to assess the certainty of evidence.

RESULTS

29 trial comparisons were identified in 1617 participants with type 1 and 2 diabetes who were predominantly middle aged, overweight, or obese with moderately controlled type 2 diabetes treated by hyperglycaemia drugs or insulin. Low GI/GL dietary patterns reduced HbA1c in comparison with higher GI/GL control diets (mean difference −0.31% (95% confidence interval −0.42 to −0.19%), P<0.001; substantial heterogeneity, I2=75%, P<0.001). Reductions occurred also in fasting glucose, LDL-C, non-HDL-C, apo B, triglycerides, body weight, BMI, systolic blood pressure (dose-response), and CRP (P<0.05), but not blood insulin, HDL-C, waist circumference, or diastolic blood pressure. A positive dose-response gradient was seen for the difference in GL and HbA1c and for absolute dietary GI and SBP (P<0.05). The certainty of evidence was high for the reduction in HbA1c and moderate for most secondary outcomes, with downgrades due mainly to imprecision.

CONCLUSIONS

This synthesis suggests that low GI/GL dietary patterns result in small important improvements in established targets of glycaemic control, blood lipids, adiposity, blood pressure, and inflammation beyond concurrent treatment with hyperglycaemia drugs or insulin, predominantly in adults with moderately controlled type 1 and type 2 diabetes. The available evidence provides a good indication of the likely benefit in this population.

STUDY REGISTRATION

ClinicalTrials.gov NCT04045938.

An optimal glycemic load range is better for reducing obesity and diabetes risk among middle-aged and elderly adults

Background

Due to the lack of evidence, advice pertaining to glycemic load (GL) can be misleading. Does the excessive restriction of GL, mostly through an extreme reduction in carbohydrate intake, result in a relatively high intake of fat and protein and result in overweight and obesity? This study was performed to initially explore the optimal GL range.

Methods

A cross-sectional study involving 2029 participants aged 40 years or older in Guangzhou, China was conducted. Participants were divided into four groups according to cluster analysis. Dietary data were assessed using a previously validated 3-day food record.

Results

Instead of participants with the highest [cluster 1, median (interquartile ranges) GL was 112(107–119)/1000 kcal] and the lowest GL intake [cluster 4, 90(82–96)/1000 kcal], those with moderate GL intakes [clusters 2 and 3, 93(85–102) and 93(85–99)/1000 kcal, respectively] had a lower prevalence of overweight, obesity and diabetes. In addition, clusters 2 and 3 were more consistent with the macronutrient intake reference with adequate micronutrient intake. Therefore, the optimal GL range was determined to be (85–100)/1000 kcal, rather than “lower is better”.

Conclusions

Reducing the GL intake to prevent diabetes deserves more attention in the context of a balanced diet. An appropriate GL may be better than excessive restriction.

Evidence generated from a realist synthesis of trials on educational weight loss interventions in type 2 diabetes mellitus

BACKGROUND

Obesity and diabetes are major public health problems. Current approaches to weight loss show varying success. Complex community-based interventions work through several interconnected stages. An individual's actions in response to an intervention depend on many known and unknown factors, which vary among individuals.

AIM

To conduct a realist synthesis to identify in which context, for whom, in what circumstances, and how weight loss interventions work in obese or overweight individuals with type 2 diabetes.

METHODS

A total of 49 trials identified during a systematic review were subsequently analysed using realist methodology. This iterative process involved hypothesis generation about how participants within a particular context respond to an intervention's resources producing the outcomes. We used established behaviour change theory to look for repeating themes. Theory and 'mechanisms' were tested against the literature on what is shown to be effective. Where established theory was lacking, we discussed issues during discussion groups with individuals living with the condition to generate our own programme theories.

RESULTS

Mechanisms that were repeatedly identified included high-frequency contact with those delivering the intervention, social support, education increasing awareness of diabetes-related modifiable risk factors, motivational interviewing and counselling, goal-setting, self-monitoring and feedback and meal replacements. The central theme underlying successful mechanisms was personalising each intervention component to the participants' gender, culture and family setting.

CONCLUSION

This is the first comprehensive realist synthesis in this field. Our findings suggest that, for weight loss interventions to be successful in those with diabetes, they must be personalized to the individual and their specific context.

Factors affecting weight loss variability in obesity

Current obesity treatment strategies include diet, exercise, bariatric surgery, and a limited but growing repertoire of medications. Individual weight loss in response to each of these strategies is highly variable. Here we review research into factors potentially contributing to inter-individual variability in response to treatments for obesity, with a focus on studies in humans. Well-recognized factors associated with weight loss capacity include diet adherence, physical activity, sex, age, and specific medications. However, following control for each of these, differences in weight loss appear to persist in response to behavioral, pharmacological and surgical interventions. Adaptation to energy deficit involves complex feedback mechanisms, and inter-individual differences likely to arise from a host of poorly defined genetic factors, as well as differential responses in neurohormonal mechanisms (including gastrointestinal peptides), metabolic efficiency and capacity of tissues, non-exercise activity thermogenesis, thermogenic response to food, and in gut microbiome. A better understanding of the factors involved in inter-individual variability in response to therapies will guide more personalized approaches to the treatment of obesity.

Kinetic Approach to the Influence of Chia Flour on Glucose Bioaccessibility from Hydrothermally Treated Maize and Quinoa Starch

Starch structure and bioactive ingredients play an implicit role in the control of glucose release at intestinal level reducing the risk of inadequate metabolic response(s). This study performs a comparative kinetic approach to glucose release from hydrothermally treated (HT) maize (MS) and quinoa (QS) starch. Besides, chia flour (CF) (20%, w/w) was added to evaluate its influence of on the apparent diffusion coefficients (Dapp) when subjected to simulated gastrointestinal digestion. Hepatocyte cultures were used to monitor mitochondrial enzymes activity (test MTT) to bioaccessible glucose concentrations. With an increasing temperature, Dapp for both QS and its mixtures with CF were kept unaltered, while those for MS were disrupted progressively affecting glucose bioaccessibility. Principal component analysis revealed differences between maize and quinoa starches, but common features in the corresponding mixtures with CF. Data indicated that quinoa starch helps controlling glucose release and that addition of CF decreased mitochondrial activity in presence of insulin.

Educational weight loss interventions in obese and overweight adults with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

AIM

The worldwide prevalence of type 2 diabetes mellitus is increasing, with most individuals with the disease being overweight or obese. Weight loss can reduce disease-related morbidity and mortality and weight losses of 10-15 kg have been shown to reverse type 2 diabetes. This review aimed to determine the effectiveness of community-based educational interventions for weight loss in type 2 diabetes.

METHODS

This is a systematic review and meta-analysis of randomized controlled trials (RCT) in obese or overweight adults, aged 18-75 years, with a diagnosis of type 2 diabetes. Primary outcomes were weight and/or BMI. CINAHL, MEDLINE, Embase, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from inception to June 2019. Trials were classified into specified a priori comparisons according to intervention type. A pooled standardized mean difference (SMD) (from baseline to follow-up) and 95% confidence intervals (95% CI) between trial groups (difference-in-difference) were estimated through random-effects meta-analyses using the inverse variance method. Heterogeneity was quantified using I² and publication bias was explored visually using funnel plots.

RESULTS

Some 7383 records were screened; 228 full-text articles were assessed and 49 RCTs (n = 12 461 participants) were included in this review, with 44 being suitable for inclusion into the meta-analysis. Pooled estimates of education combined with low-calorie, low-carbohydrate meal replacements (SMD = -2.48, 95% CI -3.59, -1.49, I²  = 98%) or diets (SMD = -1.25, 95% CI -2.11, -0.39, I²  = 95%) or low-fat meal replacements (SMD = -1.15, 95%CI -2.05, -1.09, I²  = 85%) appeared most effective.

CONCLUSION

Low-calorie, low-carbohydrate meal replacements or diets combined with education appear the most promising interventions to achieve the largest weight and BMI reductions in people with type 2 diabetes.

Lifestyle modification approaches for the treatment of obesity in adults

The U.S. Preventive Services Task Force has recommended that primary care clinicians screen all adults for obesity and provide those affected intensive multicomponent behavioral interventions. Approximately 95 million U.S. adults qualify for such care, also referred to as lifestyle modification. Using the Guidelines (2013) for Managing Overweight and Obesity in Adults (hereafter, Obesity Guidelines) as a framework, this article reviews the principal components of comprehensive lifestyle modification, which include diet, physical activity, and behavior therapy. To lose weight, the Obesity Guidelines recommend participation for 6 months in high-intensity programs that provide 14 or more counseling sessions with a trained interventionist. When provided face-to-face individual or group treatment, participants lose up to 8 kg (8% of weight) in 6 months and experience improvements in cardiovascular disease risk factors and quality of life. To prevent weight regain, the Obesity Guidelines recommend participation for 1 year in weight-loss-maintenance programs that provide at least monthly counseling. High levels of physical activity, frequent monitoring of body weight, and consumption of a reduced-calorie diet are associated with long-term weight loss. Investigators currently are seeking to increase the availability of lifestyle modification by delivering it in community-based programs, as well as on digital platforms (e.g., Internet and Smartphone). Digitally delivered programs lower costs and expand treatment reach; their efficacy is likely to improve further with the addition of new technologies for monitoring food intake, activity, and weight. Ultimately, to improve long-term weight management, individual lifestyle counseling must be joined with collective and institutional efforts to improve the nation's eating and activity environments. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Dietary Micronutrient Intake of Participants in a "Partners Together in Health" Cardiac Rehabilitation Intervention

PURPOSE

Current guidelines for cardiovascular health emphasize a "dietary pattern" approach that could be expected to increase intakes of micronutrients in addition to altering the macronutrient profile. However, the effect of interventions such as cardiac rehabilitation on the micronutrient quality of the diet has not been evaluated. Therefore, the goal of this study was to investigate changes in micronutrient intake of cardiac rehabilitation participants over time.

METHODS

This was a secondary analysis of data from a randomized clinical trial that assessed the effects of the Partners Together in Health intervention on physical activity and healthy eating behaviors. The intake of 9 micronutrients important in cardiovascular health was assessed using 3-d food records. A micronutrient adequacy score was evaluated at 3 time points (baseline, 3 and 6 mo). Changes over time in micronutrient intake were assessed using a general linear model.

RESULTS

Sixty-eight participants who were enrolled in the Partners Together in Health interventional trial completed the study. There was no significant difference in the mean micronutrient score at any time point. Intake of individual micronutrients did not improve over the 6-mo time frame with the exception of vitamin E, (8.7 mg vs 6.5 mg for at 6 vs 3 mo, P = .02). The proportion of participants with intakes meeting the Dietary Recommended Intake for each nutrient also remained the same over time.

CONCLUSION

Although cardiac rehabilitation programs may be effective in altering the macronutrient composition, improvements to overall diet quality may be tempered by a lack of improvement in intake of micronutrients.

Low-glycemic index diets as an intervention for diabetes: a systematic review and meta-analysis

BACKGROUND

Low-glycemic index (GI) diets are thought to reduce postprandial glycemia, resulting in more stable blood glucose concentrations.

OBJECTIVE

We hypothesized that low-GI diets would be superior to other diet types in lowering measures of blood glucose control in people with type 1 or type 2 diabetes, or impaired glucose tolerance.

METHODS

We searched PubMed, the Cochrane Library, EMBASE, and clinical trials registries for published and unpublished studies up until 1 March, 2019. We included 54 randomized controlled trials in adults or children with impaired glucose tolerance, type 1 diabetes, or type 2 diabetes. Continuous data were synthesized using a random effects, inverse variance model, and presented as standardized mean differences with 95% CIs.

RESULTS

Low-GI diets were effective at reducing glycated hemoglobin (HbA1c), fasting glucose, BMI, total cholesterol, and LDL, but had no effect on fasting insulin, HOMA-IR, HDL, triglycerides, or insulin requirements. The reduction in fasting glucose and HbA1c was inversely correlated with body weight. The greatest reduction in fasting blood glucose was seen in the studies of the longest duration.

CONCLUSIONS

Low-GI diets may be useful for glycemic control and may reduce body weight in people with prediabetes or diabetes.

Determination of glycemic index of enteral formulas used in clinical practice

Glycemic Index (GI) is a measure of carbohydrate quality and is recognised as a valid and reproducible method of classifying carbohydrate foods according to its effects on postprandial glycaemia. In this randomised crossover trial (RBR-7rjx3k) we determined the GI of nine enteral formulas, following the Food and Agriculture Organisation/World Health Organisation method. Forty healthy participants were included in the study (85% female mean age 27.1 ± 6.7 years). GI of the enteral formulas ranged from 40.5 to 85.2; four formulas had high GI (Nutrienteral 1.5^®, Novasource GI Control^®, Diamax^®, Isosource Soya^®), two intermediate GI (Fresubin 1.2 HP Fibre^®, Nutrison Energy Multifiber 1.5^®) and three low GI (Trophic 1.5^®, Glucerna^®, Novasource GC HP^®). The GI coefficient of variation ranged from 22.9% to 83.6%. The effect of the enteral formulas with low GI in glycemic control of patients with enteral nutrition prescription needs to be test in future studies.

Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations

While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill’s criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost–benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.

Impact of different dietary approaches on blood lipid control in patients with type 2 diabetes mellitus: a systematic review and network meta-analysis

The aim of this study was to assess the effects of different dietary approaches on low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglyceride (TG) levels in patients with type 2 diabetes (T2D) by applying network meta-analysis (NMA). Systematic electronic and hand searches were conducted until January 2018. Randomized controlled trials (RCTs) with an intervention period of ≥ 12 weeks, focussing on adults with T2D, and comparing dietary approaches regarding LDL, HDL or TGs, were included. For each outcome measure, random effects NMA was performed in order to determine the effect of each dietary approach compared to every other dietary intervention. Mean differences (MDs) and 95% confidence intervals (95% CIs) were calculated, and for the ranking, the surface under the cumulative ranking curves (SUCRA) was determined. Additionally, the credibility of evidence was evaluated. 52 RCTs (44 for LDL, 48 for HDL and 52 for TGs) comparing nine dietary approaches (low fat, vegetarian, Mediterranean, high protein, moderate carbohydrate, low carbohydrate, control, low glycaemic index/glycaemic load and Palaeolithic diet) enrolling 5360 T2D patients were included. The vegetarian diet most effectively reduced LDL levels [MD (95% CI): - 0.33 (- 0.55, - 0.12) mmol/L; compared to the control diet]. The Mediterranean diet beneficially raised HDL [MD (95% CI): 0.09 (0.04, 0.15) mmol/L] and decreased TG levels [MD (95% CI): - 0.41 (- 0.72, - 0.10) mmol/L] compared to the control diet. The Mediterranean diet was the most effective dietary approach to manage diabetic dyslipidaemia altogether (SUCRA: 79%). The overall findings are mainly limited by low credibility of evidence.

The rationale and design of the personal diet study, a randomized clinical trial evaluating a personalized approach to weight loss in individuals with pre-diabetes and early-stage type 2 diabetes

Weight loss reduces the risk of type 2 diabetes mellitus (T2D) in overweight and obese individuals. Although the physiological response to food varies among individuals, standard dietary interventions use a "one-size-fits-all" approach. The Personal Diet Study aims to evaluate two dietary interventions targeting weight loss in people with prediabetes and T2D: (1) a low-fat diet, and (2) a personalized diet using a machine-learning algorithm that predicts glycemic response to meals. Changes in body weight, body composition, and resting energy expenditure will be compared over a 6-month intervention period and a subsequent 6-month observation period intended to assess maintenance effects. The behavioral intervention is delivered via mobile health technology using the Social Cognitive Theory. Here, we describe the design, interventions, and methods used.

Low glycaemic index diets as an intervention for obesity: a systematic review and meta-analysis

OBJECTIVES

Low glycaemic index (GI) diets may aid in weight loss by reducing postprandial blood glucose excursions, leading to more stable blood glucose concentrations and therefore a reduction in hunger. To test this hypothesis, we conducted a systematic review and meta-analysis of randomized controlled trials comparing low GI diets with other diet types.

METHODS

We included 101 studies involving 109 study arms and 8,527 participants. We meta-analysed the studies using a random-effects model and conducted subgroup analyses and meta-regression based on control diet, blood glucose control, baseline BMI and dietary GI.

RESULTS

Low GI diets resulted in small but significant improvements in body weight, BMI, LDL and total cholesterol overall, although no individual control diet was significantly different from low GI diets. Studies in people with normal blood glucose who achieved a difference in GI of 20 points or more resulted in a larger reduction in body weight (SMD = -0.26; 95% CIs [-0.43, -0.09]), and total cholesterol (SMD = -0.24; 95% CIs [-0.42, -0.05]) than studies that only achieved a smaller reduction in GI.

CONCLUSIONS

Low GI diets, especially diets achieving a substantial decrease in GI, were moderately effective in lowering body weight. However, efforts should be made to increase compliance with low GI diets, in order for them to be effective in people with overweight and obesity.

Effects of low-carbohydrate- compared with low-fat-diet interventions on metabolic control in people with type 2 diabetes: a systematic review including GRADE assessments

Background

It remains uncertain which diet is best for people with type 2 diabetes (T2D).

Objective

We compared the effects of dietary carbohydrate restriction with fat restriction on markers of metabolic syndrome and quality of life in people with T2D.

Design

This systematic review of randomized controlled trials (RCTs) and controlled clinical trials (CCTs) compares the effects of a low-carbohydrate [≤40% of energy (%)] diet with those of a low-fat (≤30%) diet over a period of ≥4 wk in patients with T2D. Two investigators independently selected studies, extracted data, and assessed risk of bias. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach was used to assess the certainty of evidence. Pooled mean differences (MDs) and 95% CIs were calculated with the use of a random-effects model.

Results

Thirty-three RCTs and 3 CCTs (n = 2161) were included. Glycated hemoglobin declined more in people who consumed low-carbohydrate food than in those who consumed low-fat food in the short term (MD: -1.38%; 95% CI: -2.64%, -0.11%; very-low-certainty evidence). At 1 y, the MD was reduced to -0.36% (95% CI: -0.58%, -0.14%; low-certainty evidence); at 2 y, the difference had disappeared. There is low to high (majority moderate) certainty for small improvements of unclear clinical importance in plasma glucose, triglycerides, and HDL concentrations favoring low-carbohydrate food at half of the prespecified time points. There was little to no difference in LDL concentration or any of the secondary outcomes (body weight, waist circumference, blood pressure, quality of life) in response to either of the diets (very-low- to high-certainty evidence).

Conclusions

Currently available data provide low- to moderate-certainty evidence that dietary carbohydrate restriction to a maximum of 40% yields slightly better metabolic control of uncertain clinical importance than reduction in fat to a maximum of 30% in people with T2D. This systematic review is registered at http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017052467 as CRD42017052467.

Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and meta-analysis

Nutrition therapy is considered a key component of diabetes management, yet evidence around the ideal macronutrient composition of the diet remains inconclusive. A systematic review and meta-analysis was performed to assess the effects of carbohydrate-restricted diets (≤45% of total energy) compared to high carbohydrate diets (>45% of total energy) on glycemic control in adults with diabetes mellitus. Six databases were searched for articles published between January 1980 and August 2016. Primary outcome was between-group difference in HbA1c change. Individual effect sizes were standardized, and a meta-analysis performed to calculate pooled effect size using random effects. 25 RCTs involving 2412 participants were included. Carbohydrate-restricted diets, in particular those that restrict carbohydrate to <26% of total energy, produced greater reductions in HbA1c at 3 months (WMD -0.47%, 95% CI: -0.71, -0.23) and 6 months (WMD -0.36%, 95% CI: -0.62, -0.09), with no significant difference at 12 or 24 months. There was no difference between moderately restricted (26-45% of total energy) and high carbohydrate diets at any time point. Although there are issues with the quality of the evidence, this review suggests that carbohydrate-restricted diets could be offered to people living with diabetes as part of an individualised management plan.

A greater glycemic load reduction was associated with a lower diabetes risk in pre-diabetic patients who consume a high glycemic load diet

Few prospective studies evaluating the association between dietary glycemic load (GL) and diabetes have accounted for changes in GL. However, the diet of patients could be modified in response to an awareness of pre-diabetes. The aim of this study was to examine the longitudinal associations between changes in GL and the incidence of diabetes among pre-diabetic patients. We hypothesized that subjects with low and high baseline GL would show different correlations with diabetes. A total of 493 pre-diabetic patients (142 men and 351 women) between 40 and 79 years of age were included in this study. Dietary records and oral glucose tolerance tests were conducted every year. The participants were divided into low- and high-GL groups based on baseline GL. During a median 4 years of follow-up, 108 incident cases of diabetes were identified. Among participants with a high baseline GL, the incidence of diabetes increased with decreasing GL reduction, and the multivariate-adjusted HR (95% CI) was 2.34 (1.27-4.29) when comparing the lowest to the highest tertiles; however, among those with a low baseline GL, no significant association was observed. Regardless of baseline GL status, the incidence of diabetes was higher in individuals with a high follow-up GL than in those with a low follow-up GL, and the multivariate-adjusted HR (95% CI) was 1.64 (1.09-2.45). In conclusion, a greater GL reduction was associated with a lower diabetes risk in pre-diabetic patients with a high dietary GL. In patients with pre-diabetes and a low dietary GL, further reductions in GL did not show any additional effects.

The effect of dietary glycemic index and glycemic load on inflammatory biomarkers: a systematic review and meta-analysis of randomized clinical trials

Background

To our knowledge, there is no study available that summarizes earlier findings on the effect of dietary glycemic index (GI) and glycemic load (GL) on inflammatory biomarkers.

Objective

This systematic review and meta-analysis was conducted to systematically review the available clinical trials that examined the effects of low-GI (LGI) and low-GL (LGL) diets on several inflammatory biomarkers in adults.

Design

We searched for relevant articles published up to June 2017 through PubMed, Medline, SCOPUS, EMBASE, and Google Scholar with the use of relevant keywords. Clinical trials that examined the effect of dietary GI and GL on inflammation in adults were included.

Results

Overall, 28 randomized controlled trials (RCTs) including 2961 participants (59% women, 41% men) were included in this meta-analysis. By combining findings from 14 studies on high-sensitivity C-reactive protein (hs-CRP) concentrations, we found no significant effect of LGI or LGL diets on serum hs-CRP concentrations compared with the control diet [weighted mean difference (WMD) for dietary GI: -0.05 mg/L (95% CI: -0.21, 0.10 mg/L); and WMD for dietary GL: 0.08 mg/L (95% CI: -0.26, 0.42 mg/L), respectively]. After combining effect sizes from 5 studies, we did not find significant changes in serum tumor necrosis factor α (TNF-α) concentrations comparing control diets with LGI (WMD: -0.18 mg/L; 95% CI: -0.43, 0.06 mg/L) or LGL (WMD: -0.20 mg/L; 95% CI: -0.33, 0.07 mg/L) diets. Significant changes were also not seen in leptin and interleukin 6 (IL-6) concentrations after the consumption of LGI or LGL diets.

Conclusions

We did not find any significant effect of dietary GI or GL on serum concentrations of inflammatory cytokines, including hs-CRP, leptin, IL-6, and TNF-α in adults. Additional RCTs-in particular, feeding trials-are required to shed light on this issue.

The Science of Obesity Management: An Endocrine Society Scientific Statement

The prevalence of obesity, measured by body mass index, has risen to unacceptable levels in both men and women in the United States and worldwide with resultant hazardous health implications. Genetic, environmental, and behavioral factors influence the development of obesity, and both the general public and health professionals stigmatize those who suffer from the disease. Obesity is associated with and contributes to a shortened life span, type 2 diabetes mellitus, cardiovascular disease, some cancers, kidney disease, obstructive sleep apnea, gout, osteoarthritis, and hepatobiliary disease, among others. Weight loss reduces all of these diseases in a dose-related manner-the more weight lost, the better the outcome. The phenotype of "medically healthy obesity" appears to be a transient state that progresses over time to an unhealthy phenotype, especially in children and adolescents. Weight loss is best achieved by reducing energy intake and increasing energy expenditure. Programs that are effective for weight loss include peer-reviewed and approved lifestyle modification programs, diets, commercial weight-loss programs, exercise programs, medications, and surgery. Over-the-counter herbal preparations that some patients use to treat obesity have limited, if any, data documenting their efficacy or safety, and there are few regulatory requirements. Weight regain is expected in all patients, especially when treatment is discontinued. When making treatment decisions, clinicians should consider body fat distribution and individual health risks in addition to body mass index.

The Effect of Dietary Glycaemic Index on Glycaemia in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: The increasing prevalence of diabetes in the United Kingdom and worldwide calls for new approaches to its management, and diets with low glycaemic index have been proposed as a useful means for managing glucose response. However, there are conflicting reports and differences in the results of studies in terms of their effectiveness. Furthermore, the impact of low-glycaemic index diets and their long-term use in patients with type 2 diabetes remains unclear. Objectives: The objective of this study was to conduct a systematic review and meta-analysis of the effect of low-glycaemic index diets in patients with type 2 diabetes. Methods: Search methods: Randomised controlled studies were selected from a number of databases (EBSCOHost with links to Health Research databases, PubMed, and grey literature) based on the Population, Intervention, Comparator, Outcomes and Study designs (PICOS) framework. The search terms included synonyms and Medical Subject Headings (MeSH) and involved the use of Boolean operators (AND/OR) which allowed the combination of words and search terms. Selection criteria: As per the selection criteria, the following types of articles were selected: studies on randomised controlled trials, with year of publication between 2008 and 2018, including patients with type 2 diabetes. Thus, studies involving patients with gestational and type 1 diabetes were excluded, as were observational studies. Nine articles which met the inclusion criteria were selected for the systematic review, whereas only six articles which met the criteria were included in the meta-analysis. Data collection and analysis: Studies were evaluated for quality and risk of bias. In addition, heterogeneity, meta-analysis, and sensitivity tests of the extracted data were carried out using Review Manager 5.3 (Review Manager, 2014). Results: The findings of the systematic review showed that the low-glycaemic index (low-GI) diet resulted in a significant improvement (<0.05) in glycated haemoglobin (HbA1c) in two studies: low-GI diet Δ = −0.5% (95% CI, −0.61% to −0.39%) vs. high-cereal fibre diet Δ = −0.18% (95% CI, −0.29% to −0.07%); and low-GI legume diet Δ = −0.5% (95%, −0.6% to −0.4%) vs. high-wheat fibre diet Δ = −0.3% (95% Cl, −0.4 to −0.2%). There was a slight improvement in one study (low glycaemic response = 6.5% (6.3–7.1) vs. control = 6.6% (6.3–7.0) and no significant difference (p > 0.05) in four studies compared with the control diet. Four studies showed improvements in fasting blood glucose in low-GI diets compared to higher-GI diets or control: low-GI diet = 150.8 ± 8.7 vs. higher-GI diet = 157.8 ± 10.4 mg/dL, mean ± SD p = 0.43; low-GI diet = 127.7 vs. high-cereal fibre diet = 136.8 mg/dL, p = 0.02; low-GI diet = 6.5 (5.6–8.4) vs. standard diabetic diet = 6.7 (6.1–7.5) mmol/L, median and interquartile range p > 0.05; and low-GI diet = 7.3 ± 0.3 vs. conventional carbohydrate exchange diet = 7.7 ± 0.4 mmol/L, mean ± SEM (Standard Error of Mean) p < 0.05. The results of the meta-analysis and sensitivity tests demonstrated significant differences (p < 0.001 and p < 0.001, respectively) between the low-GI diet and the higher-GI diet or control diet in relation to glycated haemoglobin. Differences between the low-GI diet and higher-GI diet or control were significant (p < 0.05) with respect to the fasting blood glucose following meta-analysis. Conclusion: The low-GI diet is more effective in controlling glycated haemoglobin and fasting blood glucose compared with a higher-GI diet or control in patients with type 2 diabetes.

A network meta-analysis on the comparative efficacy of different dietary approaches on glycaemic control in patients with type 2 diabetes mellitus

The aim of the present study is to assess the comparative efficacy of different dietary approaches on glycaemic control in patients with type 2 diabetes mellitus using a systematic review of the literature. Electronic and hand searches were performed until July 2017. The inclusion criteria were defined as follows: (1) randomized trial with a dietary approach; (2) adults with type 2 diabetes mellitus; (3) outcome either HbA1c (%) and/or fasting glucose (mmol/l); (4) minimum intervention period of 12 weeks. For each outcome measure, random effects network meta-analysis was performed in order to determine the pooled effect of each intervention relative to each of the other interventions. A total of 56 trials comparing nine dietary approaches (low-fat, Vegetarian, Mediterranean, high-protein, moderate-carbohydrate, low-carbohydrate, control, low GI/GL, Palaeolithic) enrolling 4937 participants were included. For reducing HbA1c, the low-carbohydrate diet was ranked as the best dietary approach (SUCRA: 84%), followed by the Mediterranean diet (80%) and Palaeolithic diet (76%) compared to a control diet. For reducing fasting glucose, the Mediterranean diet (88%) was ranked as the best approach, followed by Palaeolithic diet (71%) and Vegetarian diet (63%). The network analysis also revealed that all dietary approaches significantly reduce HbA1c (− 0.82 to − 0.47% reduction) and fasting glucose (− 1.61 to − 1.00 mmol/l reduction) compared to a control diet. According to the network meta-analysis the Mediterranean diet is the most effective and efficacious dietary approach to improve glycaemic control in type 2 diabetes patients.

Multidisciplinary Team-Based Obesity Treatment in Patients With Diabetes: Current Practices and the State of the Science

IN BRIEF Rates of obesity and diabetes are growing, as are their costs. Because the two diseases share many key determinants, the paradigms for their treatment overlap. For both, optimal treatment involves a multidisciplinary team following the Chronic Care Model of health care delivery. Combined treatment programs that include 1) a low-calorie diet individualized to patients' preferences, 2) structured exercise that is also tailored to each patient, and 3) psychotherapy induce the largest weight changes in patients with diabetes. Although diet alone can achieve weight loss, exercise and cognitive behavioral therapy components can enhance the effects of dietary modification. A multidisciplinary team that includes a physician with expertise in pharmacotherapy, a nurse and/or nurse practitioner, a dietitian, an exercise physiologist, and a psychologist can provide a comprehensive weight loss program combining the most effective interventions from each discipline.

Effect of weight reduction on glycated haemoglobin in weight loss trials in patients with type 2 diabetes

AIM

To quantify the effect of weight loss on glycated haemoglobin (HbA1c) at group level, based on data from published weight loss trials in overweight and obese patients with type 2 diabetes (T2D).

METHODS

A systematic literature search in MEDLINE, EMBASE and Cochrane CENTRAL (January 1990 through December 2012) was conducted to identify prospective trials of energy-reduced diets, obesity drugs or bariatric surgery in adult, overweight and obese patients with T2D. Based on clinical data with follow-up from 3 to 24 months, a linear model was developed to describe the effect of weight reduction on HbA1c.

RESULTS

The literature search identified 58 eligible articles consisting of 124 treatment groups and 17 204 subjects, yielding a total of 250 data points with concurrent mean changes from baseline in weight and HbA1c. The model-based analyses indicated a linear relationship between weight loss and HbA1c reduction, with an estimated mean HbA1c reduction of 0.1 percentage points for each 1 kg of reduced body weight for the overall population. Baseline HbA1c was a significant covariate for the relationship between weight loss and HbA1c: high HbA1c at baseline was associated with a greater reduction in HbA1c for the same degree of weight loss. The collected trial data also indicated weight-loss-dependent reductions in antidiabetic medication.

CONCLUSIONS

At group level, weight loss in obese and overweight patients with T2D was consistently accompanied by HbA1c reduction in a dose-dependent manner. The model developed in the present study estimates that for each kg of mean weight loss, there is a mean HbA1c reduction of 0.1 percentage points. HbA1c-lowering is greater in populations with poor glycaemic control than in well controlled populations with the same degree of weight loss. This summary of data from previous trials regarding the effect of weight reduction on HbA1c may be used to support the design and interpretation of future studies that aim to demonstrate the efficacy of weight loss interventions for T2D treatment.

Intensive Lifestyle Intervention for Obesity: Principles, Practices, and Results

Using the Guidelines for the Management of Overweight and Obesity in Adults as a framework, this article reviews intensive lifestyle interventions for weight loss. The Guidelines recommend a minimum of 6 months of high-intensity, comprehensive lifestyle intervention, consisting of a reduced-calorie diet, increased physical activity, and behavior therapy. Persons with obesity typically lose approximately 8 kg (approximately 8% of initial weight) with this approach, accompanied by improvements in health and quality of life. To prevent weight regain, the Guidelines recommend a 1-year weight loss maintenance program that includes at least monthly counseling with a trained interventionist. Lifestyle interventions usually are delivered in-person; however, treatment increasingly is being disseminated through community- and commercial-based programs, as well as delivered by telephone, Internet, and smartphone platforms. These latter modalities expand treatment reach but usually produce smaller weight losses than in-person interventions. The review concludes with an examination of challenges in weight management.

Improving pregnancy outcome in obese women: the UK Pregnancies Better Eating and Activity randomised controlled Trial

Background

Obesity in pregnancy is associated with insulin resistance, which underpins many common complications including gestational diabetes mellitus (GDM) and fetal macrosomia.

Objectives

To assess the effect of a complex behavioural intervention based on diet and physical activity (PA) on the risk of GDM and delivery of a large-for-gestational age (LGA) infant.

Design

Three phases: (1) the development phase, (2) the pilot study and (3) a multicentre randomised controlled trial (RCT) comparing a behavioural intervention to improve glycaemic control with standard antenatal care in obese pregnant women. A cost–utility analysis was undertaken to estimate the cost-effectiveness of the health training (intervention) over and above standard care (control).

Setting

Pilot study: antenatal clinics in four inner-city UK hospitals. RCT: eight antenatal clinics in eight UK inner-city hospitals.

Participants

Women were eligible for inclusion if they had a body mass index of ≥ 30 kg/m2, were pregnant with a single fetus and at 15+0to 18+6weeks’ gestation, were able to give written informed consent and were without predefined disorders.

Intervention

The intervention comprised an initial session with a health trainer, followed by eight weekly sessions. Dietary advice recommended foods with a low dietary glycaemic index, avoidance of sugar-sweetened beverages and reduced saturated fats. Women were encouraged to increase daily PA.

Main outcome measures

Development phase: intervention development, acceptability and optimal approach for delivery. Pilot study: change in dietary and PA behaviours at 28 weeks’ gestation. RCT: the primary outcome of the RCT was, for the mother, GDM [as measured by the International Association of the Diabetes and Pregnancy Study Groups (IADPSG)’s diagnostic criteria] and, for the infant, LGA delivery (i.e. customised birthweight ≥ 90th centile for gestational age).

Results

Development phase: following a literature meta-analysis, a study of dietary intention questionnaires and semistructured interviews, an intervention based on behavioural science was developed that incorporated optimal and acceptable methods for delivery. Pilot study: the pilot study demonstrated improvement in dietary behaviours in the intervention compared with the standard care arm but no increase in objectively measured PA. Process evaluation demonstrated feasibility and general acceptability. RCT: the RCT showed no effect of the intervention on GDM in obese pregnant women or the number of deliveries of LGA infants. There was a reduction in dietary glycaemic load (GL) and reduced saturated fat intake, an increase in PA and a modest reduction in gestational weight gain, all secondary outcomes. Lower than expected was the number of LGA infant deliveries in all women, which suggested that universal screening for GDM with IADPSG’s diagnostic criteria, and subsequent treatment, may reduce the number of deliveries of LGA infants. According to the cost–utility analysis, the estimated probability that the UK Pregnancies Better Eating and Activity Trial (UPBEAT) behavioural intervention is cost-effective at the £30,000/quality-adjusted life-year willingness-to-pay threshold was 1%.

Limitations

Included the high refusal rate for participation and self-reported assessment of diet and PA.

Conclusions

The UPBEAT intervention, an intense theoretically based intervention in obese pregnant women, did not reduce the risk of GDM in women or the number of LGA infant deliveries, despite successfully reducing the dietary GL. Based on total cost to the NHS provider and health gains, the UPBEAT intervention provided no supporting evidence to suggest that the intervention represents value for money based on the National Institute for Health and Care Excellence benchmarks for cost-effectiveness.

Future work

Alternative strategies for reducing the risk of GDM in obese pregnant women and the number of LGA infant deliveries should be considered, including development of clinically effective interventions to prevent obesity in women of reproductive age, of clinically effective interventions to reduce weight retention following pregnancy and of risk stratification tools in early pregnancy.

Trial registration

Current Controlled Trials ISRCTN89971375 and UK Clinical Research Network Portfolio 5035.

Funding

This project was funded by the NIHR Programme Grant for Applied Research programme and will be published in full inProgramme Grants for Applied Research, Vol. 5, No. 10. See the NIHR journals library website for further project information. Contributions to funding were also provided by the Chief Scientist Office CZB/4/680, Scottish Government Health Directorates, Edinburgh; Guys and St Thomas’ Charity, Tommy’s Charity (Lucilla Poston, Annette L Briley, Paul T Seed) and the NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London, UK and the Academy of Finland, Finland. Keith M Godfrey was supported by the National Institute for Health Research through the NIHR Southampton Biomedical Research Centre. Lucilla Poston and Keith M Godfrey were supported by the European Union’s Seventh Framework Programme (FP7/2007-2013), project EarlyNutrition under grant agreement number 289346.

The effects of meal glycemic load on blood glucose levels of adults with different body mass indexes

AIMS

The aim was to determine the effect of meal glycemic load (GL) on blood glucose levels of healthy people with different body mass indexes (BMIs).

METHODS

Thirty healthy controls were included in this study. The participants were divided into two groups according to their BMI as normal group (BMI = 18.5-24.9 kg/m², n = 15) and overweight group (BMI = 25.0-29.9 kg/m², n = 15). Dietary assessment was done by the 24-h recall method for 3 successive days. Cases were fed by breakfasts with two different GL on consecutive days. Energy values of the test meal, adjusted to meet 25% of daily energy requirements of each case, were identical in low and high GL meal (483 kcal and 482 kcal, respectively). Finger-prick capillary blood samples were taken on 0, 15, 30, 45, 60, 90, and 120 min.

RESULTS

Average daily energy intake in normal and overweight group was found as 2514.3 ± 223.8 kcal, 2064.1 ± 521.6 kcal and 2211.4 ± 368.7 kcal, 2494.8 ± 918 kcal in males and females, respectively. Blood glucose level was increased and remained more stable in both high GL meal groups compared to low (P < 0.05). The effects of GL on BMI classified groups were also found different. High GL meal was found to be more effective for increasing blood glucose level, especially on overweight group (P < 0.05).

CONCLUSIONS

The effects of GL meal were found to be different on normal and overweight individuals. The high GL meals were more effective to increase the blood glucose level than low GL meal, especially on overweight people.

Management of Obesity

This review examines weight loss and accompanying improvements in obesity-related comorbidities produced by intensive lifestyle intervention, pharmacotherapy, and bariatric surgery. Obese individuals lose approximately 6 to 8 kg (approximately 6% to 8% of initial weight) with 6 months of participation in a high-intensity lifestyle intervention (≥ 14 treatment visits) consisting of diet, physical activity, and behavior therapy. Such losses reduce progression to type 2 diabetes in at-risk people and decrease blood pressure and triglyceride levels. All diets, regardless of macronutrient composition, can produce clinically meaningful weight loss (> 5%) if they induce a deficit ≥ 500 kcal/d. Physical activity of 150 to 180 min/wk yields modest short-term weight loss compared with diet but contributes to improvements in obesity-related conditions. Gradual weight regain is common after lifestyle intervention but can be prevented by continued participation in monthly weight loss maintenance sessions, as well as by high levels of physical activity (ie, 200 to 300 min/wk). Patients unable to reduce satisfactorily with lifestyle intervention may be candidates for pharmacotherapy, recommended as an adjunct. Five medications have been approved by the US Food and Drug Administration for chronic weight management, and each has its own risk/benefit profile. The addition of these medications to lifestyle intervention increases mean weight loss by 2.5 to 8.9 kg compared with placebo. Patients with severe obesity who are unable to reduce successfully with lifestyle intervention and pharmacotherapy are eligible for bariatric surgery, including Roux-en-Y gastric bypass, sleeve gastrectomy, or adjustable gastric banding. The first two procedures yield long-term (≥ 3 years) reductions of ≥ 20% of initial weight that are associated with decreases in morbidity and potentially mortality. Greater resources and dissemination efforts are needed to increase the availability of these three approaches for the millions of Americans who would benefit from them.

Behavioral Treatment of the Patient with Obesity

Advisory panels encourage persons with obesity to lose 5% to 10% of body weight, which can be achieved with dietary change, increased physical activity, and behavioral therapy. Patients participate in weekly individual or group treatment sessions delivered in-person or by telephone. Large-scale trials have demonstrated the effectiveness of this approach, with resulting improvement in cardiovascular disease risk factors. Weight regain is common. Several strategies improve weight loss maintenance, including monthly or more frequent follow-up with an interventionist. Digitally-delivered approaches are promising because they have the potential to reach more individuals.

Obese Patients with Type 2 Diabetes on Conventional Versus Intensive Insulin Therapy: Efficacy of Low-Calorie Dietary Intervention

INTRODUCTION

The aim of this prospective study was to assess the results of a standard low-calorie dietary intervention (7.5 MJ/day) on body weight (BW) and the metabolic profile of obese patients with type 2 diabetes mellitus (T2DM) on intensive insulin therapy (IIT: 4 insulin injections/day) versus conventional insulin therapy (CIT: 2/3 insulin injections/day).

METHODS

A total of 60 patients (n = 60, 23 males and 37 postmenopausal females) were recruited and categorized into two groups according to the scheme of insulin treatment. Thirty were on IIT (13 males and 17 females) and an equal number on CIT (10 males and 20 females). BW, body mass index (BMI), HbA1c, and metabolic parameters were compared at 6 and 12 months after baseline.

RESULTS

Significant reductions were observed in the BW, BMI, HbA1c (p ≤ 0.001 for all) and cholesterol (p ≤ 0.05) at 6 months post-intervention. At 1 year, median BW reduction was 4.5 kg (3.3, 5.8) for patients on IIT and 4.8 kg (3.6, 7.0) for those on CIT. The 12-month dietary intervention increased prevalence of normoglycemia in the IIT group and reduced the prevalence of obesity prevalence among the CIT participants (all p < 0.001). CIT patients with BW reduction ≥5.0% demonstrated 11-fold greater chances of being normoglycemic (odds ratio 11.3, 95% CI 1.1-110.5). BW reduction ≥7.0% was associated with CIT, being overweight, and having normal HDLc, LDLc, and cholesterol levels. A reduction in BW between 5.0% and 6.9% was associated with IIT, normoglycemia, and obesity.

CONCLUSION

A 12-month 1800-kcal dietary intervention achieved significant BW and HbA1c reductions irrespectively of insulin regimen. CIT was associated with BW reduction greater than 8.0%, whereas IIT was associated with higher rates of normoglycemia.

Effects of partners together in health intervention on physical activity and healthy eating behaviors: a pilot study

BACKGROUND

Despite proven efficacy of cardiac rehabilitation (CR) in helping patients initiate physical activity and healthy eating changes, less than 50% of CR participants maintain changes 6 months later.

OBJECTIVE

The objective of this feasibility study was to test the Partners Together in Health (PaTH) intervention versus usual care in improving physical activity and healthy eating behaviors in coronary artery bypass graft surgery patients and their spouses.

METHODS

An experimental, 2-group (n = 17 couples/group), repeated-measures design was used. Coronary artery bypass surgery patients in both groups participated in phase II outpatient CR. Spouses in the PaTH group attended CR with the patient and were asked to make the same physical activity and healthy eating changes as patients did. Spouses in the usual care attended educational classes with patients. It was theorized that "2 persons would be better than 1" at making changes and sticking with them in the long-term. Physical activity behavior was measured using the Actiheart accelerometer; the activity biomarker was an exercise tolerance test. Eating behavior was measured using 3-day food records; the biomarker was the lipid profile. Data were collected at baseline (entrance in CR), at 3 months (post-CR), and at 6 months. Changes over time were examined using Mann-Whitney U statistics and effect sizes.

RESULTS

The PaTH intervention was successful primarily in demonstrating improved trends in healthy eating behavior for patients and spouses. No differences were found between the PaTH and usual care patients or spouses at 3 or 6 months in the number of minutes per week of physical activity. By 6 months, patients in both groups were, on average, below the national guidelines for PA recommendations (≥150 min/wk at >3 metabolic equivalents).

CONCLUSIONS

The couple-focused PaTH intervention demonstrated promise in offsetting the decline in dietary adherence typically seen 6 months after CR.

The effect of macronutrients on glycaemic control: a systematic review of dietary randomised controlled trials in overweight and obese adults with type 2 diabetes in which there was no difference in weight loss between treatment groups

Weight loss is crucial for treating type 2 diabetes mellitus (T2DM). It remains unclear which dietary intervention is best for optimising glycaemic control, or whether weight loss itself is the main reason behind observed improvements. The objective of this study was to assess the effects of various dietary interventions on glycaemic control in overweight and obese adults with T2DM when controlling for weight loss between dietary interventions. A systematic review of randomised controlled trials (RCT) was conducted. Electronic searches of Medline, Embase, Cinahl and Web of Science databases were conducted. Inclusion criteria included RCT with minimum 6 months duration, with participants having BMI≥25·0 kg/m2, a diagnosis of T2DM using HbA1c, and no statistically significant difference in mean weight loss at the end point of intervention between dietary arms. Results showed that eleven studies met the inclusion criteria. Only four RCT indicated the benefit of a particular dietary intervention over another in improving HbA1c levels, including the Mediterranean, vegan and low glycaemic index (GI) diets. However the findings from one of the four studies showing a significant benefit are questionable because of failure to control for diabetes medications and poor adherence to the prescribed diets. In conclusion there is currently insufficient evidence to suggest that any particular diet is superior in treating overweight and obese patients with T2DM. Although the Mediterranean, vegan and low-GI diets appear to be promising, further research that controls for weight loss and the effects of diabetes medications in larger samples is needed.

Proportion of Brazilian diabetes patients that achieve treatment goals: implications for better quality of care

BACKGROUND

Diabetes and its complications are substantial causes of morbidity and mortality, and caused approximately 5.1 million deaths worldwide in 2013. Early detection and treatment of diabetes complications can prevent their progression.

OBJECT

This study compared the proportions of patients with type 1 and 2 diabetes mellitus (T1DM and T2DM, respectively) who achieved the goals of good clinical control.

METHODS

Adults and elderly patients with T1DM and T2DM at a public outpatient endocrinology service in Brazil were retrospectively evaluated between 2012 and 2013. Clinical and socio demographic data were obtained from medical records and evaluated in accordance with the Brazilian Diabetes Society Guidelines. Care process measures, outcomes indicators, and supporting process measures were evaluated.

RESULTS

A total of 1031 records were analyzed: 29 and 71 % of patients had T1DM and T2DM, respectively. T2DM patients had significantly higher BMI than T1DM patients (overweight and obesity in 85.1 vs. 47.5 %, p < 0.01). The follow-up periods for diabetes and number of clinical visits to the endocrinology service were significantly greater among T1DM patients than T2DM patients (p < 0.01). However, T2DM patients required significantly more other (i.e., non-endocrinological) healthcare services (p < 0.01). HbA1c was significantly lower in T2DM patients (p < 0.01). Moreover, blood pressure and triglycerides were significantly higher in T2DM patients (p < 0.01), whereas total cholesterol and low-density lipoprotein were significantly lower in T2DM patients (p < 0.01). Only 0.5 % of the patients achieved all targets, and 1.1 % did not achieve any.

CONCLUSIONS

The achievement of goals of good clinical practice varies among the parameters evaluated. Almost no patients achieved all targets. Many patients are overweight and do not achieve targets for HbA1c, lipid profile, or blood pressure control.

Effects of high vs low glycemic index of dietary carbohydrate on cardiovascular disease risk factors and insulin sensitivity: the OmniCarb randomized clinical trial

IMPORTANCE

Foods that have similar carbohydrate content can differ in the amount they raise blood glucose. The effects of this property, called the glycemic index, on risk factors for cardiovascular disease and diabetes are not well understood.

OBJECTIVE

To determine the effect of glycemic index and amount of total dietary carbohydrate on risk factors for cardiovascular disease and diabetes.

DESIGN, SETTING, AND PARTICIPANTS

Randomized crossover-controlled feeding trial conducted in research units in academic medical centers, in which 163 overweight adults (systolic blood pressure, 120-159 mm Hg) were given 4 complete diets that contained all of their meals, snacks, and calorie-containing beverages, each for 5 weeks, and completed at least 2 study diets. The first participant was enrolled April 1, 2008; the last participant finished December 22, 2010. For any pair of the 4 diets, there were 135 to 150 participants contributing at least 1 primary outcome measure.

INTERVENTIONS

(1) A high-glycemic index (65% on the glucose scale), high-carbohydrate diet (58% energy); (2) a low-glycemic index (40%), high-carbohydrate diet; (3) a high-glycemic index, low-carbohydrate diet (40% energy); and (4) a low-glycemic index, low-carbohydrate diet. Each diet was based on a healthful DASH-type diet.

MAIN OUTCOMES AND MEASURES

The 5 primary outcomes were insulin sensitivity, determined from the areas under the curves of glucose and insulin levels during an oral glucose tolerance test; levels of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides; and systolic blood pressure.

RESULTS

At high dietary carbohydrate content, the low- compared with high-glycemic index level decreased insulin sensitivity from 8.9 to 7.1 units (-20%, P = .002); increased LDL cholesterol from 139 to 147 mg/dL (6%, P ≤ .001); and did not affect levels of HDL cholesterol, triglycerides, or blood pressure. At low carbohydrate content, the low- compared with high-glycemic index level did not affect the outcomes except for decreasing triglycerides from 91 to 86 mg/dL (-5%, P = .02). In the primary diet contrast, the low-glycemic index, low-carbohydrate diet, compared with the high-glycemic index, high-carbohydrate diet, did not affect insulin sensitivity, systolic blood pressure, LDL cholesterol, or HDL cholesterol but did lower triglycerides from 111 to 86 mg/dL (-23%, P ≤ .001).

CONCLUSIONS AND RELEVANCE

In this 5-week controlled feeding study, diets with low glycemic index of dietary carbohydrate, compared with high glycemic index of dietary carbohydrate, did not result in improvements in insulin sensitivity, lipid levels, or systolic blood pressure. In the context of an overall DASH-type diet, using glycemic index to select specific foods may not improve cardiovascular risk factors or insulin resistance.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00608049.

An automated telephone nutrition support system for Spanish-speaking patients with diabetes

In the United States, Spanish-speaking patients with diabetes often receive inadequate dietary counseling. Providing language and culture-concordant dietary counseling on an ongoing basis is critical to diabetes self-care. To determine if automated telephone nutrition support (ATNS) counseling could help patients improve glycemic control by duplicating a successful pilot in Mexico in a Spanish-speaking population in Oakland, California. A prospective randomized open-label trial with blinded endpoint assessment (PROBE) was performed. The participants were seventy-five adult patients with diabetes receiving care at a federally qualified health center in Oakland, California. ATNS, a computerized system that dialed patients on their phones, prompted them in Spanish to enter (via keypad) portions consumed in the prior 24 hours of various cultural-specific dietary items, and then provided dietary feedback based on proportion of high versus low glycemic index foods consumed. The control group received the same ATNS phone calls 14 weeks after enrollment. The primary outcome was hemoglobin A1c % (A1c) 12 weeks following enrollment. Participants had no significant improvement in A1c (-0.3% in the control arm, -0.1% in the intervention arm, P = .41 for any difference) or any secondary parameters. In our study, an ATNS system did not improve diabetes control in a Spanish-speaking population in Oakland.

Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic review and meta-analysis

BACKGROUND

Some popular weight loss diets restricting carbohydrates (CHO) claim to be more effective, and have additional health benefits in preventing cardiovascular disease compared to balanced weight loss diets.

METHODS AND FINDINGS

We compared the effects of low CHO and isoenergetic balanced weight loss diets in overweight and obese adults assessed in randomised controlled trials (minimum follow-up of 12 weeks), and summarised the effects on weight, as well as cardiovascular and diabetes risk. Dietary criteria were derived from existing macronutrient recommendations. We searched Medline, EMBASE and CENTRAL (19 March 2014). Analysis was stratified by outcomes at 3-6 months and 1-2 years, and participants with diabetes were analysed separately. We evaluated dietary adherence and used GRADE to assess the quality of evidence. We calculated mean differences (MD) and performed random-effects meta-analysis. Nineteen trials were included (n = 3209); 3 had adequate allocation concealment. In non-diabetic participants, our analysis showed little or no difference in mean weight loss in the two groups at 3-6 months (MD 0.74 kg, 95%CI -1.49 to 0.01 kg; I2 = 53%; n = 1745, 14 trials; moderate quality evidence) and 1-2 years (MD 0.48 kg, 95%CI -1.44 kg to 0.49 kg; I2 = 12%; n = 1025; 7 trials, moderate quality evidence). Furthermore, little or no difference was detected at 3-6 months and 1-2 years for blood pressure, LDL, HDL and total cholesterol, triglycerides and fasting blood glucose (>914 participants). In diabetic participants, findings showed a similar pattern.

CONCLUSIONS

Trials show weight loss in the short-term irrespective of whether the diet is low CHO or balanced. There is probably little or no difference in weight loss and changes in cardiovascular risk factors up to two years of follow-up when overweight and obese adults, with or without type 2 diabetes, are randomised to low CHO diets and isoenergetic balanced weight loss diets.

Association between carbohydrate quality and inflammatory markers: systematic review of observational and interventional studies

BACKGROUND

Chronic low-grade inflammation is a likely intermediary between quality of carbohydrate and chronic disease risk.

OBJECTIVE

We conducted a systematic literature search to evaluate the relevance of carbohydrate quality on inflammatory markers in observational and intervention studies.

DESIGN

MEDLINE, EMBASE, and the Cochrane Library were searched for studies on associations between glycemic index (GI), glycemic load (GL), dietary fiber or fiber supplements or whole grain intake, and high-sensitivity C-reactive protein (hsCRP) or interleukin 6 (IL-6). Included studies had to be conducted on adults (healthy, overweight, with type 2 diabetes or metabolic syndrome features, but without inflammatory disease) with ≥20 participants and a 3-wk duration.

RESULTS

In total, 22 of the 60 studies that met our inclusion criteria examined GI/GL: 5 of 9 observational studies reported lower concentrations of hsCRP or IL-6 among persons with a lower dietary GI/GL; 3 of 13 intervention studies showed significant antiinflammatory effects of a low-GI/GL diet, and 4 further studies suggested beneficial effects (trends or effects in a subgroup). For fiber intake, 13 of 16 observational studies reported an inverse relation with hsCRP or IL-6, but only 1 of 11 intervention studies showed a significant antiinflammatory effect of fiber intake, and a further trial reported a beneficial trend. For whole-grain intake, 6 of 7 observational studies observed an inverse association with inflammatory markers, but only 1 of 7 intervention studies reported significant antiinflammatory effects, 1 further study was suggestive (in a subgroup) of such, and another study found an adverse effect (trend only).

CONCLUSIONS

Evidence from intervention studies for antiinflammatory benefits is less consistent for higher-fiber or whole-grain diets than for low-GI/GL diets. Benefits of higher fiber and whole-grain intakes suggested by observational studies may reflect confounding.

Impact of behavioral interventions in the management of adults with type 2 diabetes mellitus

Research on the role of behavior change as an efficacious intervention for adults with type 2 diabetes is evolving. Searching PubMed and Ovid Medline, we identified and reviewed primarily randomized controlled trials from 2010 to 2013 of adults managing type 2 diabetes without insulin. All studies are evaluated in terms of the rigor of their design and their impact on glycosylated hemoglobin. The most efficacious interventions appear to be low-carbohydrate/glycemic load diets, combined aerobic and resistance training, and self-monitoring of blood glucose, which educates patients about the impact of their food selections and physical activity on their blood glucose.

Nutrition therapy recommendations for the management of adults with diabetes

There is no standard meal plan or eating pattern that works universally for all people with diabetes. In order to be effective, nutrition therapy should be individualized for each patient/client based on his or her individual health goals; personal and cultural preferences; health literacy and numeracy; access to healthful choices; and readiness, willingness, and ability to change. Nutrition interventions should emphasize a variety of minimally processed nutrient dense foods in appropriate portion sizes as part of a healthful eating pattern and provide the individual with diabetes with practical tools for day-to-day food plan and behavior change that can be maintained over the long term.

Long-term effects of low glycemic index/load vs. high glycemic index/load diets on parameters of obesity and obesity-associated risks: a systematic review and meta-analysis

AIM

The aim of the present meta-analysis was to investigate the long-term effects of glycemic index-related diets in the management of obesity with a special emphasis on the potential benefits of low glycemic index/load (GI/GL) in the prevention of obesity-associated risks.

DATA SYNTHESIS

Electronic searches for randomized controlled trials (RCTs) comparing low glycemic index/load versus high glycemic index/load diets were performed in MEDLINE, EMBASE and the Cochrane Library. Outcome of interest markers included anthropometric data as well as biomarkers of CVD and glycemic control. Study specific weighted mean differences were pooled using a random effect model. 14 studies were included in the primary meta-analysis. Weighted mean differences in change of C-reactive protein [WMD: -0.43 mg/dl, (95% CI -0.78 to -0.09), p = 0.01], and fasting insulin [WMD: -5.16 pmol/L, (95% CI -8.45 to -1.88), p = 0.002] were significantly more pronounced in benefit of low GI/GL diets. However decrease in fat free mass [WMD: -1.04 kg (95% CI -1.73 to -0.35), p = 0.003] was significantly more pronounced following low GI/GL diets as well. No significant changes were observed for blood lipids, anthropometric measures, HbA1c and fasting glucose. Sensitivity analysis was performed for RCTs excluding subjects with type 2 diabetes. Decreases in C-reactive protein and fasting insulin remained statistically significant in the low GI/GL subgroups.

CONCLUSIONS

The present systematic review provides evidence for beneficial effects of long-term interventions administering a low glycemic index/load diet with respect to fasting insulin and pro-inflammatory markers such as C-reactive protein which might prove to be helpful in the primary prevention of obesity-associated diseases.

Developing a complex intervention for diet and activity behaviour change in obese pregnant women (the UPBEAT trial); assessment of behavioural change and process evaluation in a pilot randomised controlled trial

BACKGROUND

Complex interventions in obese pregnant women should be theoretically based, feasible and shown to demonstrate anticipated behavioural change prior to inception of large randomised controlled trials (RCTs). The aim was to determine if a) a complex intervention in obese pregnant women leads to anticipated changes in diet and physical activity behaviours, and b) to refine the intervention protocol through process evaluation of intervention fidelity.

METHODS

We undertook a pilot RCT of a complex intervention in obese pregnant women, comparing routine antenatal care with an intervention to reduce dietary glycaemic load and saturated fat intake, and increase physical activity. Subjects included 183 obese pregnant women (mean BMI 36.3 kg/m2).

RESULTS

Compared to women in the control arm, women in the intervention arm had a significant reduction in dietary glycaemic load (33 points, 95% CI -47 to -20), (p < 0.001) and saturated fat intake (-1.6% energy, 95% CI -2.8 to -0. 3) at 28 weeks' gestation. Objectively measured physical activity did not change. Physical discomfort and sustained barriers to physical activity were common at 28 weeks' gestation. Process evaluation identified barriers to recruitment, group attendance and compliance, leading to modification of intervention delivery.

CONCLUSIONS

This pilot trial of a complex intervention in obese pregnant women suggests greater potential for change in dietary intake than for change in physical activity, and through process evaluation illustrates the considerable advantage of performing an exploratory trial of a complex intervention in obese pregnant women before undertaking a large RCT.

TRIAL REGISTRATION

TRIAL REGISTRATION NUMBER

ISRCTN89971375.

A randomized comparison of a commercially available portion-controlled weight-loss intervention with a diabetes self-management education program

OBJECTIVE

This study examined the efficacy of a commercially available, portion-controlled diet (PCD) on body weight and HbA1c over 6 months in obese patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

One-hundred participants with a mean±s.d. age of 55.6±10.6 year, body weight of 102.9±18.4 kg and HbA1c of 7.7±1.3% were randomly assigned to a 9-session group lifestyle intervention that included a PCD or to a 9-session group program of diabetes self-management education (DSME). Participants in the two groups were prescribed the same goals for energy intake (1250-1550 kcal per day) and physical activity (200 min per week).

RESULTS

While both groups produced significant improvements in weight and HbA1c after 6 months of treatment, PCD participants lost 7.3 kg [95% confidence interval (CI): -5.8 to -8.8 kg], compared with 2.2 kg (95% CI: -0.7 to -3.7 kg) in the DSME group (P<0.0001). Significantly more PCD than DSME participants lost 5% of initial weight (54.0% vs 14.0%, P<0.0001) and 10% (26.0% vs 6.0%, P<0.0001). HbA1c declined by 0.7% (95% CI: -0.4 to -1.0%) in the PCD group, compared with 0.4% (95% CI: -0.1 to -0.7%) in DSME (P<0.026). Across both groups, larger weight losses were associated with greater reductions in HbA1c (r=0.52, P<0.0001).

CONCLUSIONS

These findings demonstrate that a commercially available portion-controlled meal plan can induce clinically meaningful improvements in weight and glycemic control in obese individuals with type 2 diabetes. These data have implications for the management of obesity in primary care, as now provided by the Centers for Medicare and Medicaid Services.