Metabolic and cardiovascular effects of very-low-calorie diet therapy in obese patients with Type 2 diabetes in secondary failure: outcomes after 1 year

The effect of diet-induced weight loss on circulating homocysteine levels in people with obesity and type 2 diabetes

BACKGROUND/AIMS

Having type 2 diabetes (T2D) in combination with being overweight results in an additional increase in cardiovascular disease (CVD) risk. In addition, T2D and obesity are associated with increased levels of total homocysteine (tHcy), possibly contributing to the CVD risk. Weight loss dieting has positive effects on several CVD risk factors, but whether it affects tHcy remains unclear. Therefore, the aim of this study was to determine the effect of a calorie restricted diet on tHcy in overweight people with T2D.

METHODS

In this post-hoc analysis of the POWER study, adults with T2D and a BMI greater than 27 kg/m² were included from the outpatient diabetes clinic of the Erasmus Medical Center, Rotterdam. The patients were subjected to a very low-calorie diet with fortified meal replacements for 20 weeks. Before and after this intervention, blood samples were collected to measure tHcy and other CVD risk factors like glycaemic and lipid parameters.

RESULTS

161 overweight participants with T2D were included, with a mean age of 54 years (range 26-74), mean weight of 104.6 ± 19.9 kg and mean HbA1c of 62.7 ± 14.3 mmol/mol. At baseline, men displayed higher tHcy than women, and tHcy level was positively correlated with body weight and triglyceride levels, while it was negatively correlated with renal function and HDL cholesterol. During the intervention, bodyweight was reduced by a mean of 9.7% (from 104.6 ± 19.9 to 94.5 ± 18.1 kg p < 0.001), and all measured glycaemic and lipid blood parameters improved significantly. However, tHcy remained unchanged (from 12.1 ± 4.1 to 12.1 ± 4.2 umol/L, p = 0.880). The change in tHcy during the intervention was negatively associated with the change in weight and BMI (p = 0.01 and p = 0.008, respectively). People who lost < 10 kg (n = 92) had a mean tHcy change of -0.47 umol/L, while people who lost more than ≥ 10 kg (n = 69) had a mean tHcy change of 0.60 umol/L (p = 0.021).

CONCLUSION

In conclusion, our data show that a calorie restricted diet does not affect tHcy in people with T2D and obesity, despite the use of meal replacements fortified with folic acid and vitamin B12. Our data showed a negative correlation between change in tHcy levels and weight loss, suggesting that people who lost more weight (> 10 kg) showed an increase in tHcy. Future studies should explore the potential increase in tHcy induced by weight loss dieting and target the question if tHcy reduction strategies during weight loss could be clinically beneficial.

Very low energy diets before nonbariatric surgery: A systematic review and meta-analysis

BACKGROUND

Very low energy diets serve as an intensive approach to weight loss in a short period of time. Although the preoperative use of very low energy diets to optimize patients with obesity before bariatric surgery is well established, the evidence for very low energy diets before other types of surgery remains unclear. The aim of this review was to determine the impact of preoperative very low energy diets on perioperative outcomes in nonbariatric surgery.

METHODS

Medline, EMBASE, CENTRAL, and PubMed were systematically searched from inception through to July 2021. Articles were included if they evaluated very low energy diets use before any type of nonbariatric surgery. The primary outcome was postoperative morbidity. Secondary outcomes included compliance, safety, and preoperative weight loss. A pairwise meta-analyses using inverse variance random effects was performed.

RESULTS

From 792 citations, 13 studies with 395 patients (mean age: 56.5 years, 55.8% female) receiving very low energy diets preoperatively in preparation for nonbariatric surgery were included. Mean duration of preoperative very low energy diets was 6.6 weeks (range, 0.42-17 weeks). Target daily caloric intake ranged from 450 kcal to 1,400 kcal. Compliance with very low energy diets ranged from 94% to 100%. The mean preoperative weight loss ranged from 3.2 kg to 19.2 kg. There were no significant differences in postoperative morbidity (odds ratio, 1.10; 95% confidence interval, 0.64-1.91; P = .72), operative time (standard mean difference -0.35; 95% confidence interval, 1.13-0.43, P = .38), or postoperative length of stay (standard mean difference 0.40, 95% confidence interval -0.11-0.91, P = .12) with very low energy diets.

CONCLUSION

Although the currently available evidence is heterogenous, preoperative very low energy diets are safe, well tolerated, and effectively induce preoperative weight loss in patients undergoing nonbariatric surgery for both benign and malignant disease. Further prospective studies are warranted.

Metabolic Impact of Intermittent Fasting in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of Interventional Studies

CONTEXT

Intermittent fasting (IF) has been proposed as a weight-loss strategy with additional cardiometabolic benefits in individuals with obesity. Despite its growing popularity, the effect of IF in patients with type 2 diabetes (T2DM) remains unclear.

OBJECTIVE

We conducted a systematic review and meta-analysis to evaluate the metabolic impact of IF compared to standard diet in patients with T2DM.

METHODS

Embase, PubMed, and clinicaltrials.gov between 1950 and August 12, 2020 were searched for randomized, diet-controlled studies evaluating any IF intervention in adults with T2DM. We examined the impact of IF on weight loss and glucose-lowering by calculating pooled estimates of the absolute differences in body weight and glycated hemoglobin A1c (HbA1c) compared to a control group using a random-effects model.

RESULTS

Seven studies (n = 338 participants; mean body mass index [BMI] 35.65, mean baseline HbA1c 8.8%) met our inclusion criteria. IF induced a greater decrease in body weight by -1.89 kg (95% CI, -2.91 to -0.86 kg) compared to a regular diet, with no significant between-study heterogeneity (I2 21.0%, P = .28). The additional weight loss induced by IF was greater in studies with a heavier population (BMI > 36) (-3.43 kg [95% CI, -5.72 to -1.15 kg]) and in studies of shorter duration (≤ 4 months) (-3.73 kg [95% CI, -7.11 to -0.36 kg]). IF was not associated with further reduction in HbA1c compared to a standard diet (HbA1c -0.11% [95% CI, -0.38% to 0.17%]).

CONCLUSION

Current evidence suggests that IF is associated with greater weight loss in patients with T2DM compared with a standard diet, with a similar impact on glycemic control.

The Effects of Very Low Energy Diets and Low Energy Diets with Exercise Training on Skeletal Muscle Mass: A Narrative Review

In recent years, very-low-energy diets (VLEDs) have been recognised as a viable strategy for improving the extent of weight loss and cardio-metabolic outcomes in people who are either overweight or obese. However, concerns exist regarding the reductions in lean body mass (LBM) during VLEDs, particularly in vulnerable demographic groups, such as middle-aged and older adults already prone to developing sarcopenia. Sarcopenia is itself associated with multiple adverse outcomes, including frailty, cardio-metabolic deterioration and increased mortality. Therefore, a number of studies investigating strategies to ameliorate this detrimental effect of VLEDs have attempted to address this concern. This narrative review explores the potential benefits and limitations of exercise and/or protein supplementation for LBM retention during VLEDs based on the available evidence. Current studies suggest that both protein supplementation and exercise training may result in improved LBM retention (and skeletal muscle function) during VLEDs. However, uncertainty remains concerning the interactions between intervention types, based on discordant outcomes reported in the literature and the heterogeneity of exercise modalities in achieving this particular outcome.

Low-energy total diet replacement intervention in patients with type 2 diabetes mellitus and obesity treated with insulin: a randomized trial

OBJECTIVES

The management of patients with long-standing type 2 diabetes and obesity receiving insulin therapy (IT) is a substantial clinical challenge. Our objective was to examine the effect of a low-energy total diet replacement (TDR) intervention versus standardized dietetic care in patients with long-standing type 2 diabetes and obesity receiving IT.

RESEARCH DESIGN AND METHODS

In a prospective randomized controlled trial, 90 participants with type 2 diabetes and obesity receiving IT were assigned to either a low-energy TDR (intervention) or standardized dietetic care (control) in an outpatient setting. The primary outcome was weight loss at 12 months with secondary outcomes including glycemic control, insulin burden and quality of life (QoL).

RESULTS

Mean weight loss at 12 months was 9.8 kg (SD 4.9) in the intervention and 5.6 kg (SD 6.1) in the control group (adjusted mean difference -4.3 kg, 95% CI -6.3 to 2.3, p<0.001). IT was discontinued in 39.4% of the intervention group compared with 5.6% of the control group among completers. Insulin requirements fell by 47.3 units (SD 36.4) in the intervention compared with 33.3 units (SD 52.9) in the control (-18.6 units, 95% CI -29.2 to -7.9, p=0.001). Glycated Hemoglobin (HbA1c) fell significantly in the intervention group (4.7 mmol/mol; p=0.02). QoL improved in the intervention group of 11.1 points (SD 21.8) compared with 0.71 points (SD 19.4) in the control (8.6 points, 95% CI 2.0 to 15.2, p=0.01).

CONCLUSIONS

Patients with advanced type 2 diabetes and obesity receiving IT achieved greater weight loss using a TDR intervention while also reducing or stopping IT and improving glycemic control and QoL. The TDR approach is a safe treatment option in this challenging patient group but requires maintenance support for long-term success.

TRIAL REGISTRATION NUMBER

ISRCTN21335883.

Efficacy of low- and very-low-energy diets in people with type 2 diabetes mellitus: A systematic review and meta-analysis of interventional studies

AIMS

To review systematically and quantify the weight loss achieved through low- (LEDs) and very-low-energy diets (VLEDs) in people with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Studies reporting the effects of diet-only interventions of up to 1600 kcal/d in people with T2DM were searched in MEDLINE, EMBASE and CINAHL up to July 2018. Changes in the primary (body weight and body mass index [BMI]) and secondary outcomes (glycated haemoglobin, blood lipids) according to energy restriction and duration of diet were modelled using restricted cubic splines.

RESULTS

Forty-four studies (3817 participants) were included. The overall quality of the evidence was moderate and limited to short-term interventions up to 4 months. Baseline mean weight and BMI were 92.1 kg and 36.6 kg/m² . VLEDs of 400 kcal/d led to 5.4% weight loss at 2 weeks, increasing to 17.9% at 3 months. More modest reductions of 7.3% were observed on LEDs of 1200 kcal/d and 2.0% on 1600 kcal/d after 3 months. No clear patterns emerged for secondary outcomes. Publication bias was significant for primary outcomes.

CONCLUSIONS

Through modelling, we were able to describe effective dietary deficit strategies to achieve weight reduction up to 4 months in people with T2DM. High-quality studies are required to further support clinical practice with evidence-based dietary interventions.

A social-network behavioral health program on sustained long-term body weight and glycemic outcomes: 2-year follow-up of a 4-month Microclinic Health Program in Jordan

The burden of chronic diseases like diabetes and obesity is rapidly increasing in low and lower-middle income countries. This work assesses the long-term efficacy of a social-network based community health program for the management and prevention of type 2 diabetes.

METHODS

The 4-month Microclinic Social Network Behavioral Health Program in Jordan (J-MCP) was an intervention for obesity and diabetes prevention and management conducted in the Kingdom of Jordan. Weight and HbA1c were collected at baseline, end of the 4-month program, and then 12 and 24 months after baseline. Multi-level longitudinal repeated measures analysis estimated the long-term change in metabolic outcomes, and estimated the intra-class correlations (ICCs) for assessing the degree of clustering that different social network levels, of microclinic group vs. classroom group vs. clinic geographic location vs. cohort temporal wave, contributed to body weight and glycemic changes.

RESULTS

Of 315 participants, 83.2% completed the J-MCP program, with 90% followup at 12-months, and 70% at 24-months. At the end of the 4-month program, participants experienced a -2.8 kg (95% CI: -3.6 to -2.1) mean body weight decrease, a corresponding -1.1 kg/m2 (-1.3 to -0.8) BMI decrease, and a -0.5% reduction in HbA1c (-0.6 to -0.3). At year 1, we observed significant mean weight reduction of -1.8 kg (-2.7 to -0.9), a corresponding -0.7 kg/m2 (-1.0 to -0.4) reduction in BMI, as well as a -0.4% (-0.6 to -0.3) sustained reduction in HbA1c. At 2 years, participants sustained mean weight loss of -1.6 kg (-2.6 to -0.5), a -0.42 kg/m2 (-0.8 to -0.04) reduction in BMI, and an absolute -1.0% (-1.1 to -0.8) sustained reduction in HbA1c. Analyzing different social network levels, classroom group explained ~50% of total clustering of total weight loss and 22% of HbA1c trajectories during the short 4 month intervention. However, during 12 and 24 month followup, microclinic social group clustering explained ~75% to 92% of long-term weight loss trajectories, and 55% of long-term HbA1c trajectories. The pattern of 1-2 year sustainability of the weight and HbA1c decreases was largely attributed to the microclinic social network clusters.

CONCLUSION

Results demonstrate that the 4-month J-MCP behavioral intervention yielded important 2-year sustained weight and HbA1c reductions, which were mostly attributed to microclinic social groups.

Bariatric surgery, lifestyle interventions and orlistat for severe obesity: the REBALANCE mixed-methods systematic review and economic evaluation

BACKGROUND

Adults with severe obesity [body mass index (BMI) of ≥ 35 kg/m2] have an increased risk of comorbidities and psychological, social and economic consequences.

OBJECTIVES

Systematically review bariatric surgery, weight-management programmes (WMPs) and orlistat pharmacotherapy for adults with severe obesity, and evaluate the feasibility, acceptability, clinical effectiveness and cost-effectiveness of treatment.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, PsycINFO, the Cochrane Central Register of Controlled Trials and the NHS Economic Evaluation Database were searched (last searched in May 2017).

REVIEW METHODS

Four systematic reviews evaluated clinical effectiveness, cost-effectiveness and qualitative evidence for adults with a BMI of ≥ 35 kg/m2. Data from meta-analyses populated a microsimulation model predicting costs, outcomes and cost-effectiveness of Roux-en-Y gastric bypass (RYGB) surgery and the most effective lifestyle WMPs over a 30-year time horizon from a NHS perspective, compared with current UK population obesity trends. Interventions were cost-effective if the additional cost of achieving a quality-adjusted life-year is < £20,000-30,000.

RESULTS

A total of 131 randomised controlled trials (RCTs), 26 UK studies, 33 qualitative studies and 46 cost-effectiveness studies were included. From RCTs, RYGB produced the greatest long-term weight change [-20.23 kg, 95% confidence interval (CI) -23.75 to -16.71 kg, at 60 months]. WMPs with very low-calorie diets (VLCDs) produced the greatest weight loss at 12 months compared with no WMPs. Adding a VLCD to a WMP gave an additional mean weight change of -4.41 kg (95% CI -5.93 to -2.88 kg) at 12 months. The intensive Look AHEAD WMP produced mean long-term weight loss of 6% in people with type 2 diabetes mellitus (at a median of 9.6 years). The microsimulation model found that WMPs were generally cost-effective compared with population obesity trends. Long-term WMP weight regain was very uncertain, apart from Look AHEAD. The addition of a VLCD to a WMP was not cost-effective compared with a WMP alone. RYGB was cost-effective compared with no surgery and WMPs, but the model did not replicate long-term cost savings found in previous studies. Qualitative data suggested that participants could be attracted to take part in WMPs through endorsement by their health-care provider or through perceiving innovative activities, with WMPs being delivered to groups. Features improving long-term weight loss included having group support, additional behavioural support, a physical activity programme to attend, a prescribed calorie diet or a calorie deficit.

LIMITATIONS

Reviewed studies often lacked generalisability to UK settings in terms of participants and resources for implementation, and usually lacked long-term follow-up (particularly for complications for surgery), leading to unrealistic weight regain assumptions. The views of potential and actual users of services were rarely reported to contribute to service design. This study may have failed to identify unpublished UK evaluations. Dual, blinded numerical data extraction was not undertaken.

CONCLUSIONS

Roux-en-Y gastric bypass was costly to deliver, but it was the most cost-effective intervention. Adding a VLCD to a WMP was not cost-effective compared with a WMP alone. Most WMPs were cost-effective compared with current population obesity trends.

FUTURE WORK

Improved reporting of WMPs is needed to allow replication, translation and further research. Qualitative research is needed with adults who are potential users of, or who fail to engage with or drop out from, WMPs. RCTs and economic evaluations in UK settings (e.g. Tier 3, commercial programmes or primary care) should evaluate VLCDs with long-term follow-up (≥ 5 years). Decision models should incorporate relevant costs, disease states and evidence-based weight regain assumptions.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016040190.

FUNDING

The National Institute for Health Research Health Technology Assessment programme. The Health Services Research Unit and Health Economics Research Unit are core funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorate.

Commercial Very Low Energy Meal Replacements for Preoperative Weight Loss in Obese Patients: a Systematic Review

BACKGROUND

This systematic review assessed feasibility and effectiveness of preoperative meal replacements to improve surgical outcomes for obese patients.

METHODS

PRISMA guidelines were followed and electronic databases searched for articles between January 1990 and March 2015.

RESULTS

Fifteen studies (942 participants including 351 controls) were included, 13 studies (n = 750) in bariatric patients. Adverse effects and dropout rates were minimal. Ten out of 14 studies achieved 5-10 % total weight loss. Six of six studies reporting liver volume achieved 10 % reduction. Endpoints for perioperative risks and outcomes were too varied to support definitive risk benefit.

CONCLUSIONS

Commercial meal replacements are feasible, have minimal side effects and facilitate weight loss and liver shrinkage in free-living obese patients awaiting elective surgery. A reduction in surgical risk is unclear.

LIMITED CARBOHYDRATE REFEEDING INSTRUCTION FOR LONG-TERM WEIGHT MAINTENANCE FOLLOWING A KETOGENIC, VERY-LOW-CALORIE MEAL PLAN

OBJECTIVE

Weight-loss maintenance following very-low-calorie meal plans is poorly studied. This report describes weight-loss efficacy and predictors of weight-loss maintenance of a ketogenic, very-low-calorie meal plan (protein-sparing modified fast, PSMF) in people with obesity.

METHODS

A total of 127 consecutive adults in the PSMF meal plan (27.2 ± 19.5 weeks) and 48 adults on a conventional, hypocaloric meal plan (23.6 ± 20.8 weeks) were retrospectively studied for percent weight change from baseline to end of intervention and at 6, 12, and 24 months postintervention. Baseline factors were analyzed for correlations with weight-loss maintenance.

RESULTS

At end of intervention, weight loss from baseline was greater for the PSMF group compared to the conventional intervention group (-12.4% vs. -2.6%; P<.001) but was similar between groups by 12 months postintervention. PSMF subjects who attended follow-up visits to receive instruction on gradual and limited carbohydrate refeeding after ketosis saw significant weight loss at the end of PSMF compared to those who did not follow-up to receive instruction (-17.5% vs. -8.0%; P<.001) and maintained greater weight loss through 12 months post-PSMF (-9.8% vs. -1.5%; P<.001). Higher baseline body mass index correlated with less weight loss at 12 months post-PSMF (P = .035).

CONCLUSION

PSMF results in effective short-term weight loss of more than 5% from baseline weight. Follow-up for limited carbohydrate refeeding instruction is important for weight-loss maintenance up to 2 years after initial weight loss.

ABBREVIATIONS

BMI = body mass index; PSMF = protein-sparing modified fast.

Optimizing management of glycaemia

The global epidemic of type 2 diabetes (T2DM) continues largely unabated due to an increasingly sedentary lifestyle and obesogenic environment. A cost-effective patient-centred approach, incorporating glucose-lowering therapy and modification of cardiovascular risk factors, could help prevent the inevitable development and progression of macrovascular and microvascular complications. Glycaemic optimization requires patient structured education, self-management and empowerment, and psychological support along with early and proactive use of glucose lowering therapies, which should be delivered in a system of care as shown by the Chronic Care Model. From diagnosis, intensive glycaemic control and individualised care is aimed at reducing complications. In older people, the goal is maintaining quality of life and minimizing morbidity, especially as overtreatment increases hypoglycaemia risk. Maintaining durable glycaemic control is challenging and complex to achieve without hypoglycaemia, weight gain and other significant adverse effects. Overcoming patient and physician barriers can help ensure adequate treatment initiation and intensification. Cardiovascular safety studies with newer glucose-lowering agents are now mandatory, with a sodium glucose co-transporter-2 inhibitor (empagliflozin), and two glucagon like peptide-1 receptor agonists (liraglutide and semaglutide) being the first to demonstrate superior CV outcomes compared with placebo.

Clinical effectiveness of very-low-energy diets in the management of weight loss: a systematic review and meta-analysis of randomized controlled trials

Guidelines suggest that very-low-energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain. Literature databases were searched from inception to November 2014. Randomized trials were included where the intervention included a VLED and the comparator was no intervention or an intervention that could be given in a general medical setting in adults that were overweight. Two reviewers characterized the population, intervention, control groups, outcomes and appraised quality. The primary outcome was weight change at 12 months from baseline. Compared with a behavioural programme alone, VLEDs combined with a behavioural programme achieved -3.9 kg [95% confidence interval (CI) -6.7 to -1.1] at 1 year. The difference at 24 months was -1.4 kg (95%CI -2.6 to -0.2) and at 38-60 months was -1.3 kg (95%CI -2.9 to 0.2). Nineteen per cent of the VLED group discontinued treatment prematurely compared with 20% of the comparator groups, relative risk 0.96 (0.56 to 1.66). One serious adverse event, hospitalization with cholecystitis, was reported in the VLED group and none in the comparator group. Very-low-energy diets with behavioural programmes achieve greater long-term weight loss than behavioural programmes alone, appear tolerable and lead to few adverse events suggesting they could be more widely used than current guidelines suggest.

Current management of diabetes mellitus and future directions in care

The last 90 years have seen considerable advances in the management of type 1 and type 2 diabetes. Prof MacLean of Guy's Hospital wrote in the Postgraduate Medical Journal in 1926 about the numerous challenges that faced patients and their healthcare professionals in delivering safe and effective diabetes care at that time. The discovery of insulin in 1922 heralded a new age in enabling long-term glycaemic control, which reduced morbidity and mortality. Thirty years later, the first oral agents for diabetes, the biguanides and sulfonylureas, appeared and freed type 2 patients from having to inject insulin following diagnosis. Improvements in insulin formulations over the decades, including rapid-acting and long-acting insulin analogues that more closely mimic physiological insulin secretion, have increased the flexibility and efficacy of type 1 diabetes management. The last two decades have seen major advances in technology, which has manifested in more accurate glucose monitoring systems and insulin delivery devices ('insulin pump'). Increased understanding of the pathophysiological deficits underlying type 2 diabetes has led to the development of targeted therapeutic approaches such as on the small intestine (glucagon-like peptide-1 receptor analogues and dipeptidyl-peptidase IV inhibitors) and kidneys (sodium-glucose cotransporter-2 inhibitors). A patient-centred approach delivered by a multidisciplinary team is now advocated. Glycaemic targets are set according to individual circumstances, taking into account factors such as weight, hypoglycaemia risk and patient preference. Stepwise treatment guidelines devised by international diabetes organisations standardise and rationalise management. Structured education programmes and psychological support are now well-established as essential for improving patient motivation and self-empowerment. Large multicentre randomised trials have confirmed the effectiveness of intensive glycaemic control on microvascular outcomes, but macrovascular outcomes and cardiovascular safety remain controversial with several glucose-lowering agents. Future directions in diabetes care include strategies such as the 'bionic pancreas', stem cell therapy and targeting the intestinal microbiome. All of these treatments are still being refined, and it may be several decades before they are clinically useful. Prevention and cure of diabetes is the Holy Grail but remain elusive due to lack of detailed understanding of the metabolic, genetic and immunological causes that underpin diabetes. Much progress has been made since the time of Prof MacLean 90 years ago, but there are still great strides to be taken before the life of the patient with diabetes improves even more significantly.

Safety and efficacy of a multiphase dietetic protocol with meal replacements including a step with very low calorie diet

To investigate safety, compliance, and efficacy, on weight loss and cardiovascular risk factors of a multiphasic dietary intervention based on meal replacements, including a period of very low calorie diet (VLCD) in a population of obese patients. Anthropometric parameters, blood tests (including insulin), dual-energy-X-ray absorptiometry (DXA), and questionnaires for the assessment of safety and compliance before and after (phase I) a 30-day VLCD, 700 kcal/day, normoproteic, 50 g/day carbohydrate, four meal replacements; (phase II) a 30-day low calorie diet (LCD), 820 kcal/day, three meal replacements plus a protein plate; (phase III) 60-day LCD, 1,100 kcal/day, two meal replacements plus two protein plates and reintroduction of small amounts of carbohydrates; (phase IV) 60-day hypocaloric balanced diet (HBD), 1,200 kcal/day, one meal replacement, two protein plates and the reintroduction of carbohydrates. 24 patients (17 females, 7 males, mean BMI 33.8±3.2 kg/m2, mean age 35.1±10.2 years) completed the study. The average weight loss was 15.4±6.7%, with a significant reduction of fat mass (from 32.8±4.7 to 26.1±6.3% p<0.05) and a relative increase of lean mass (from 61.9±4.8 to 67.1±5.9% p<0.05). An improvement of metabolic parameters and no variations of the liver and kidney functions were found. A high safety profile and an excellent dietary compliance were seen. The VLCD dietary program and the replacement dietary system described here is an effective, safe, and well-tolerated treatment for weight control.

Weight loss for women with and without polycystic ovary syndrome following a very low-calorie diet in a community-based setting with trained facilitators for 12 weeks

BACKGROUND

Polycystic ovary syndrome (PCOS) affects between 2% and 26% of reproductive-age women in the UK, and accounts for up to 75% of anovulatory infertility. The major symptoms include ovarian disruption, hyperandrogenism, insulin resistance, and polycystic ovaries. Interestingly, at least half of the women with PCOS are obese, with the excess weight playing a pathogenic role in the development and progress of the syndrome. The first-line treatment option for overweight/obese women with PCOS is diet and lifestyle interventions; however, optimal dietary guidelines are missing. Although many different dietary approaches have been investigated, data on the effectiveness of very low-calorie diets on PCOS are very limited.

MATERIALS AND METHODS

The aim of this paper was to investigate how overweight/obese women with PCOS responded to LighterLife Total, a commercial very low-calorie diet, in conjunction with group behavioral change sessions when compared to women without PCOS (non-PCOS).

RESULTS

PCOS (n=508) and non-PCOS (n=508) participants were matched for age (age ±1 unit) and body mass index (body mass index ±1 unit). A 12-week completers analysis showed that the total weight loss did not differ significantly between PCOS (n=137) and non-PCOS participants (n=137) (-18.5±6.6 kg vs -19.4±5.7 kg, P=0.190). Similarly, the percentage of weight loss achieved by both groups was not significantly different (PCOS 17.1%±5.6% vs non-PCOS 18.2%±4.4%, P=0.08).

CONCLUSION

Overall, LighterLife Total could be an effective weight-loss strategy in overweight/obese women with PCOS. However, further investigations are needed to achieve a thorough way of understanding the physiology of weight loss in PCOS.

Long-term weight loss maintenance and management following a VLCD: a 3-year outcome

BACKGROUND

Effective weight loss treatment is important as obesity has severe health and socioeconomic repercussions. Emerging evidence suggests that rapid initial weight loss results in better long-term weight loss maintenance. This remains controversial and contradicts current recommendations for slower weight loss.

AIM

To determine the effect of a very low calorie diet (VLCD) with group-based behaviour therapy on weight loss and long-term weight management by means of a retrospective database analysis.

METHODS

Data for this retrospective analysis included participants who embarked on the LighterLife Total VLCD programme between 2007 and 2010, and whose weights at baseline and at least 12 months were available (n = 5965).

RESULTS

Data were available for 5965 individuals at 1 year, 2044 at 2 years and 580 at 3 years. At baseline, the majority of individuals were Caucasian (n = 5155), female (n = 5419), ≥ 40 years old (n = 4272), 49% were within the body mass index (BMI) range of 30-35 kg/m(2) while 51% had a BMI > 35 kg/m(2) . The average initial weight of the whole cohort was 99.1 kg (SD 16.6). Initial weight and BMI at entry onto programme, as well as numbers of weeks of weight loss were all significantly associated with weight loss achieved on the first weight loss attempt. Weight lost during the initial weight loss phase was the only factor, which was significantly associated with percentage weight loss maintenance for years 1, 2, and 3.

CONCLUSION

The findings of this retrospective analysis suggest that provided a longer term weight loss management programme is adhered to, large amounts of initial weight loss can result in important longer term weight loss maintenance in motivated individuals.

Weight loss for individuals with type 2 diabetes following a very-low-calorie diet in a community-based setting with trained facilitators for 12 weeks

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Approximately 80% of people with type 2 diabetes mellitus (T2DM) are overweight or obese. Weight loss produces numerous benefits in T2DM. People with T2DM have difficulty losing and maintaining weight.

WHAT THIS STUDY ADDS

Provision of a very-low-calorie diet (VLCD) with group support and behaviour therapy for patients with T2DM is feasible within a community-based setting with trained facilitators. VLCD approaches for weight management in T2DM can achieve more than 90% of weight loss as compared with obese individuals without T2DM. Identification of the need to investigate the full impact of this approach in patients with T2DM by assessing changes in glycaemia, liver function and medication. Approximately 80% of people with type 2 diabetes mellitus (T2DM) are overweight or obese, and obesity compounds the cardiovascular risk of T2DM. The aim of this retrospective study was twofold: first, to investigate whether a 12-week community-based very-low-calorie diet (VLCD) programme can result in important weight loss; and second, to investigate any potential difference in the weight loss achieved using this community-based approach in individuals with and without T2DM. Three hundred and fifty-five participants with T2DM were matched for age, body mass index (BMI) and gender to participants without T2DM (total cohort comprised 204 males: 506 females (mean ± standard deviation); age (years) 54.0 ± 9.1; BMI (kg m(-2) ) 41.6 ± 8.1; weight (kg) 116.1 ± 25.1). The programme included a daily intake of 550 kcal in addition to group support and behaviour therapy provided by trained facilitators within a community-based setting. After 12 weeks, there was significant weight loss within each group when compared with baseline (T2DM: 115.0 ± 24.4 kg vs. 96.7 ± 21.4 kg, P < 0.0001; non-T2DM: 117.2 ± 25.8 kg vs. 97.3 ± 22.2 kg, P < 0.0001). At 12 weeks, weight change (-18.3 ± 7.3 kg vs. -19.9 ± 7.0 kg, P = 0.012) and BMI change (-6.7 ± 2.9 kg m(-2) vs. -7.1 ± 2.1 kg m(-2) , P = 0.011) were significantly less in the T2DM group when compared with the non-T2DM group. Our results suggest that the use of VLCD approaches for weight management in T2DM can achieve more than 90% of the weight loss seen in obese individuals without T2DM.

The effect of very low-calorie diets on renal and hepatic outcomes: a systematic review

Very low-calorie diets (VLCDs) are an effective means by which to induce clinically significant weight loss. However, their acceptance by health care practitioners and the public is generally lower than that for other nonsurgical weight loss methods. Whilst there is currently little evidence to suggest they have any detrimental effect on hepatic and renal health, data assessing these factors remain limited. We carried out a systematic review of the literature on randomized controlled trials that had a VLCD component and that reported outcomes for hepatic and renal health, published between January 1980 and December 2012. Cochrane criteria were followed, and eight out of 196 potential articles met the inclusion criteria. A total of 548 participants were recruited across the eight studies. All eight studies reported significant weight loss following the VLCD. Changes in hepatic and renal outcomes were variable but generally led to either no change or improvements in either of these. Due to the heterogeneity in the quality and methodology of the studies included, the effect of VLCDs on hepatic and renal outcomes remains unclear at this stage. Further standardized research is therefore required to fully assess the impact of VLCDs on these outcome measures, to better guide clinical practice.

The Prevention Of WEight Regain in diabetes type 2 (POWER) study: the effectiveness of adding a combined psychological intervention to a very low calorie diet, design and pilot data of a randomized controlled trial

Background

Obesity is of major pathogenetic importance to type 2 diabetes, it contributes to poor glycemic control and increases the risk of cardiovascular disease. Over 80% of patients with diabetes type 2 are overweight. To achieve a more favourable risk profile, changes in diet and lifestyle are needed. However, current treatment programs for obese DM type 2 patients are not effective in the long term. In this RCT, we compare the effectiveness of a Combined Psychological Intervention (CPI) and usual care in maintaining the favourable effects on weight and risk profile during 2 years of follow-up after a Very Low Calorie Diet (VLCD).

Methods and design

In a randomised parallel group intervention study, 140 patients with type 2 diabetes and overweight (BMI>27 kg/m2) will be recruited from the outpatient department of the Erasmus Medical Centre.

After obtaining ≥5% of weight loss with a VLCD, participants will be randomly assigned to CPI or usual care for 10 weeks. CPI consists of cognitive behaviour therapy, problem solving therapy and proactive coping.

Primary outcome measure is weight change (kg).

Other outcome measures are Body Mass Index (BMI = weight (kg)/length (m)2), waist circumference (cm), systolic blood pressure (mmHg), HbA1c (mmol/mol), lipid levels (LDL, HDL, TG (mmol/l) and chol/HDL-ratio), antidiabetic agents and doses, cardiovascular risk profile (UKPDS), lifestyle and quality of life (EuroQol EQ-5D). Psychosocial parameters are also studied, as secondary outcomes as well as determinants for weight loss.

When successful, we want to conduct an analysis of the cost effectiveness of the intervention as compared to usual care.

Discussion

We expect that a CPI after a VLCD will be effective in maintaining weight loss and improving cardiovascular risk and glycaemic control, while being cost-effective and improving quality of life in patients with type 2 diabetes.

Clinical trials registration

trialregister.nl NTR2264

Long-term beneficial effect of a 16-week very low calorie diet on pericardial fat in obese type 2 diabetes mellitus patients

Pericardial fat accumulation has been associated with an increased cardiovascular risk. A very low calorie diet (VLCD) improves the cardiovascular risk profile in patients with type 2 diabetes mellitus (T2DM), by improving the metabolic profile, heart function, and triglyceride (TG) stores in (non)adipose tissues. However, long-term effects of a VLCD on pericardial fat volume and tissue-specific TG accumulation have not been documented. The aim of this study was therefore to assess the effects of a 16-week VLCD and of subsequent 14 months follow-up on a regular diet on pericardial fat in relation to other TG stores in obese T2DM patients. We included 14 obese patients with insulin-treated T2DM (mean ± s.e.m.: age 53 ± 2 years; BMI 35 ± 1 kg/m(2)). Pericardial fat and other (non)adipose TG stores were measured using magnetic resonance (MR) imaging and proton spectroscopy before and after a 16-week VLCD and after a 14-month follow-up without dietary interventions. A 16-week VLCD reduced body weight, pericardial fat, hepatic TG content, visceral and subcutaneous abdominal fat volumes to 78, 83, 16, 40, and 53% of baseline values respectively, (all P < 0.05). After an additional 14 months of follow-up on a regular diet, the reduction in pericardial fat volume sustained, despite a substantial regain in body weight, visceral abdominal fat, and hepatic TG content (respectively 90, 83 and 73% of baseline values). In conclusion, VLCD-induced weight loss in obese T2DM patients is accompanied by a substantial decrease in pericardial fat volume, which is sustained even after subsequent weight regain.

Very-low-energy diets and morbidity: a systematic review of longer-term evidence

Evidence from the literature supports the safe use of very-low-energy diets (VLED) for up to 3 months in supervised conditions for patients who fail to meet a target weight loss using a standard low-fat, reduced-energy approach. There is, however, a need for longer-term outcomes on obesity and associated morbidities following a VLED. The present systematic review aims to investigate longer-term outcomes from studies using VLED, with a minimum duration of 12 months, published between January 2000 and December 2010. Studies conducted in both children and adults, with a mean/median BMI of ≥ 28 kg/m2 were included. PubMed, MEDLINE, Web of Science and Science Direct were searched. Reference lists of studies and reviews were manually searched. Weight loss or prevention of weight gain and morbidities were the main outcomes assessed. A total of thirty-two out of 894 articles met the inclusion criteria. The duration of the studies ranged from 12 months to 5 years. Periods of VLED ranged from 25 d to 9 months. Several studies incorporated aspects of behaviour therapy, exercise, low-fat diets, low-carbohydrate diets or medication. Current evidence demonstrates significant weight loss and improvements in blood pressure, waist circumference and lipid profile in the longer term following a VLED. Interpretation of the results, however, was restricted and conclusions with which to guide best practice are limited due to heterogeneity between the studies. The present review clearly identifies the need for more evidence and standardised studies to assess the longer-term benefits from weight loss achieved using VLED.

Less fat reduction per unit weight loss in type 2 diabetic compared with nondiabetic obese individuals completing a very-low-calorie diet program

The objective was to compare weight loss and change in body composition in obese subjects with and without type 2 diabetes mellitus during a very-low-calorie diet (VLCD) program. Seventy weight-matched subjects with diabetes or normal fasting glucose (controls) participated in a 24-week VLCD study. Primary end points were changes in anthropometry, body composition, and fasting plasma insulin and β-hydroxybutyrate concentrations. Fifty-one subjects (24 with diabetes) completed the study. No difference in weight loss between the 2 groups at 24 weeks was found by intention-to-treat analysis. Both groups completing the study per protocol had near-identical weight change during the program, with similar weight loss at 24 weeks (diabetes: 8.5 ± 1.3 kg vs control: 9.4 ± 1.2 kg, P = .64). Change in fat mass index correlated with change in body mass index (BMI) in both groups (diabetes: r = 0.878, control: r = 0.920, both P < .001); but change in fat mass index per unit change in BMI was less in the diabetic group compared with controls (0.574 vs 0.905 decrease, P = .003), which persisted after adjusting for age, sex, and baseline BMI (P = .008). Insulin concentrations remained higher and peak β-hydroxybutyrate concentrations were lower in the diabetic compared with the control group. While following a 24-week VLCD program, obese subjects with and without diabetes achieved comparable weight loss; but the decrease in adiposity per unit weight loss was attenuated in diabetic subjects. Hyperinsulinemia may have inhibited lipolysis in the diabetic group; however, further investigation into other factors is needed.

Quality of life in type 2 diabetes mellitus after a very low calorie diet and exercise

OBJECTIVE

To evaluate whether the addition of exercise to a very low calorie diet (VLCD) has beneficial short- and long-term effects on health-related quality of life (QoL) in obese patients with type 2 diabetes mellitus (T2DM).

METHODS

We included 27 obese, insulin-dependent T2DM patients in a 16-week VLCD study, of whom 13 participated simultaneously in an exercise program (VLCD+E). Before, immediately after and 18 months after the intervention anthropometric measurements, glucoregulation and QoL (SF-36, HADS, NHP and MFI-20) were assessed. Patients were compared to healthy lean and obese (matched for body mass index) controls matched for gender and age.

RESULTS

At baseline, T2DM patients had significantly worse QoL scores in 18 and 14 of the 22 subscales of the QoL questionnaires, compared to lean and obese controls, resp. The 16-week VLCD (n=27) decreased bodyweight (-25.4±1.3 kg, p<0.0001, p=0.179 between groups), and improved glucoregulation (HbA1c -1.3±0.3%, p<0.0001, p=0.488 between groups) and 9 (VLCD-only) and 11 (VLCD+E) of the 22 subscales of QoL. After 18 months, in the VLCD+E group the QoL subscales did not differ from those in obese controls and only 4 of the 22 subscales were significantly worse compared to lean controls. However, in the VLCD-only group 17 and 13 of the 22 QoL subscales were significantly worse compared to the lean and obese controls, resp.

CONCLUSION

A 16-week VLCD induces considerable weight loss, metabolic amelioration, and major improvements in QoL in obese T2DM patients. The addition of exercise is of paramount importance for the maintenance of better QoL.

Four therapeutic diets: adherence and acceptability

Many health conditions are treated, at least in part, by therapeutic diets. Although the success of any intervention depends on its acceptability to the patient, the acceptability of therapeutic diets and factors that influence it have been largely neglected in nutrition research. A working definition of acceptability is proposed and an examination and summary are provided of available data on the acceptability of common diet regimens used for medical conditions. The goal is to suggest ways to improve the success of therapeutic diets. The proposed working definition of "acceptability" refers to the user's judgment of the advantages and disadvantages of a therapeutic diet-in relation to palatability, costs, and effects on eating behaviour and health-that influence the likelihood of adherence. Very low-calorie, reduced-fat omnivorous, vegetarian and vegan, and low-carbohydrate diets all achieve acceptability among the majority of users in studies of up to one year, in terms of attrition and adherence rates and results of questionnaires assessing eating behaviours. Longer studies are fewer, but they suggest that vegetarian, vegan, and reduced-fat diets are acceptable, as indicated by sustained changes in nutrient intake. Few studies of this length have been published for very low-calorie or low-carbohydrate diets. Long-term studies of adherence and acceptability of these and other therapeutic diets are warranted.

The evidence for medical nutrition therapy for type 1 and type 2 diabetes in adults

This article reviews the evidence and nutrition practice recommendations from the American Dietetic Association's nutrition practice guidelines for type 1 and type 2 diabetes in adults. The research literature was reviewed to answer nutrition practice questions and resulted in 29 recommendations. Here, we present the recommendations and provide a comprehensive and systematic review of the evidence associated with their development. Major nutrition therapy factors reviewed are carbohydrate (intake, sucrose, non-nutritive sweeteners, glycemic index, and fiber), protein intake, cardiovascular disease, and weight management. Contributing factors to nutrition therapy reviewed are physical activity and glucose monitoring. Based on individualized nutrition therapy client/patient goals and lifestyle changes the client/patient is willing and able to make, registered dietitians can select appropriate interventions based on key recommendations that include consistency in day-to-day carbohydrate intake, adjusting insulin doses to match carbohydrate intake, substitution of sucrose-containing foods, usual protein intake, cardioprotective nutrition interventions, weight management strategies, regular physical activity, and use of self-monitored blood glucose data. The evidence is strong that medical nutrition therapy provided by registered dietitians is an effective and essential therapy in the management of diabetes.

Predictors of very-low-energy diet outcome in obese women and men

OBJECTIVE

The aim of this study was to explore baseline outcome predictors of a 12-week very-low-energy diet (VLED) treatment.

METHODS

Obese patients (177 women and 90 men) started treatment. Multivariate linear and logistic regressions were used to predict weight loss (%), successful outcome (>or= 10% weight loss) and attrition. Potential predictors were anthropometry, socioeconomic variables, established questionnaires on health-related quality of life, and eating behavior, and additional questions related to dieting.

RESULTS

Mean weight loss was 13.5% (standard deviation (SD) 5.6) in women and 15.1% (6.1) in men (p = 0.054). Greater weight loss in women was predicted by having more children, lower education, and better perceived physical health (R-square (R(2)) = 12.7%), and in men by better ambulation capacity, living with a partner/children, and snacking on ice-cream more often (R(2) = 39.4%). Successful outcome in women was predicted by less obesity-related psychosocial dysfunction, and in men by better functioning in social interaction and ambulation capacity. Attrition was predicted by lower age and larger hip circumference in women, and in men by lower perceived general health. Two-week weight loss was independently associated with all outcomes except attrition in women.

CONCLUSION

Factors related to perceived physical health, social interaction, socio-economic factors, and obesity-related psychosocial problems predicted VLED outcome. The predictors differed by gender.

Prolonged caloric restriction in obese patients with type 2 diabetes mellitus decreases myocardial triglyceride content and improves myocardial function

OBJECTIVES

This study sought to assess the effects of prolonged caloric restriction in obese patients with type 2 diabetes mellitus (T2DM) on myocardial triglyceride (TG) content and myocardial function.

BACKGROUND

Myocardial TG content is increased in patients with T2DM and may reflect altered myocardial function. It is unknown whether myocardial TG content is influenced during a therapeutic intervention.

METHODS

Myocardial TG content (magnetic resonance [MR] spectroscopy), myocardial function (MR imaging), plasma hemoglobin A1c, and body mass index (BMI) were measured in 12 obese, insulin-treated T2DM patients before and after a 16-week very-low-calorie diet (VLCD) (450 kcal/day) to achieve substantial weight loss. Insulin was stopped during the VLCD.

RESULTS

The BMI decreased from 35.6 +/- 1.2 kg/m(2) (baseline, mean +/- SEM) to 27.5 +/- 1.3 kg/m(2) (after the VLCD, p < 0.001) and was associated with an improvement in hemoglobin A1c from 7.9 +/- 0.4% (baseline) to 6.3 +/- 0.3% (after the VLCD, p = 0.006). Myocardial TG content decreased from 0.88 +/- 0.12% to 0.64 +/- 0.14%, respectively (p = 0.019), and was associated with improved diastolic function (reflected by the ratio between the early and atrial filling phase) from 1.02 +/- 0.08 to 1.18 +/- 0.06, respectively (p = 0.019).

CONCLUSIONS

Prolonged caloric restriction in obese T2DM patients decreases BMI and improves glucoregulation associated with decreased myocardial TG content and improved diastolic heart function. Therefore, myocardial TG stores in obese patients with T2DM are flexible and amendable to therapeutic intervention by caloric restriction.

Dietary advice for treatment of type 2 diabetes mellitus in adults

BACKGROUND

While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available.

OBJECTIVES

To assess the effects of type and frequency of different types of dietary advice for adults with type 2 diabetes.

SEARCH STRATEGY

We carried out a comprehensive search of The Cochrane Library, MEDLINE, EMBASE, CINAHL, AMED, bibliographies and contacted relevant experts.

SELECTION CRITERIA

All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention.

DATA COLLECTION AND ANALYSIS

The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data.

MAIN RESULTS

Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias.

AUTHORS' CONCLUSIONS

There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

Sustained beneficial metabolic effects 18 months after a 30-day very low calorie diet in severely obese, insulin-treated patients with type 2 diabetes

Eighteen insulin-treated obese type 2 diabetic patients were followed for 18 months after they followed a 30-day very low calorie diet (VLCD, 450kCal/day) with the cessation of all glucose-lowering medication. After the 30-day VLCD, caloric intake was slowly increased to eucaloric and glucose-lowering medication was restarted if necessary. On day 0 and 30 of the VLCD and after 18 months follow-up, bodyweight, blood-pressure, glycaemic control and lipid levels were measured. The 30-day VLCD significantly reduced bodyweight (-11.7+/-0.7kg, mean+/-S.E.M.) and improved dyslipidaemia, hypertension and glycaemia. As a group, this effect was sustained at 18 months follow-up despite the fact that patients used less lipid-, blood-pressure- and glucose-lowering medication. Especially, the use of insulin was significantly reduced: 18 out of 18 patients on day 0 (mean 137+/-22units/day); 5 out of 18 patients at 18 months (86+/-14units/day). Patients using insulin at 18 months had regained weight to prediet levels, but still had a better cardiovascular risk profile compared with before the dietary intervention. Thus, a once-only 30-day VLCD leads to a sustained improvement in glycaemia, dyslipidaemia and blood-pressure up to 18 months follow-up in obese type 2 diabetic patients, even, although to a lesser extent, in patients who regained body-weight.

Comparison of two low-calorie diets: a prospective study of effectiveness and safety

OBJECTIVE

To evaluate the cost-effectiveness and safety of two distinct low calorie diets (LCD).

DESIGN

Prospective controlled study.

METHODS

67 obese patients [body mass index (BMI) 40 kg/m2] were included in two study groups. Group A: 26 patients followed a 458 kcal diet given in three meals for 1 month. Group B: 41 patients followed a 800 kcal diet for 3 months and with outpatient control.

MEASUREMENTS

Anthropometric, cardiovascular risk and nutritional profile changes were evaluated, as well as total direct and indirect costs, and the incidence of complications.

RESULTS

No significant initial differences were observed between the two study groups. Eighty-six point two per cent of the patients completed the therapy correctly. After treatment a significant decrease was observed in the following variables for both groups, but no differences were detected between Groups A and B: mean weight loss (A= 9.28 kg, B= 8.7 kg), ponderal loss percentage (A/B= 7.2/6.8%), glycemia (A/B= 18.6/12.1 mg/dl), systolic blood pressure (SBP) (A/B= 11.8/6.5 mmHg), diastolic blood pressure (DBP) (A/B 5.9/6.8 mmHg), and final insulin-resistance (IR) index (A= 4.4, B= 4.3). Group A had the highest drop in total cholesterol (37.7 vs 8.1 mg/dl) and triglycerides (54.4 vs 2.5 mg/dl). No changes were observed in ureic acid, renal function and serum albumin. Thirty-six patients (55.3%) suffered trivial complications associated to the VLCD (16.9% gastrointestinal, 20% anxiety), with no differences between groups. Group A patients were on sick leave due to asthenia, and two patients in this group had serious complications (transient ischemic attack and atrial fibrillation). The total cost of Group A treatment was 3018.9 against 582.6 euros for Group B.

CONCLUSIONS

The 3-month 800 kcal/day VLCD was more cost-effective and safer than the 1-month 458 kcal/day diet.

Effects of weight loss and calorie restriction on carbohydrate metabolism

PURPOSE OF REVIEW

This article provides an overview of the most recent molecular and clinical outcomes of studies that investigate the effect of weight loss and calorie restriction on carbohydrate metabolism, obtained either by dieting or bariatric surgery. It will focus on aspects of carbohydrate metabolism related to insulin action. The discussion begins by describing attempts to restrain calories by shifting the macronutrient balance from carbohydrates to a higher protein and fat content. The topics covered include insulin secretion and resistance, glucose homeostasis and allostasis, changes in the secretive patterns of adipose tissue and the entero-insular axis.

RECENT FINDINGS

Any improvement in glucose homeostasis, insulin sensitivity and secretion after a low-carbohydrate high-fat diet is still unproved. However, the restriction of dietary carbohydrate seems to reduce glycogenolysis and endogenous glucose production in type 2 diabetes mellitus, thus inducing the amelioration of plasma glucose levels, ultimately resulting in a reduction in the glycated haemoglobin concentration. The increased endogenous glucose production caused by enhanced gluconeogenesis and glycogenolysis, reduced insulin sensitivity, mainly caused by acquired defects of glucose transport and phosphorylation, and the impairment of insulin secretion all together contribute to maintain a chronic status of hyperglycaemia. Weight loss and calorie restriction restore glucose homeostasis and produce changes in the secretive activities of adipose tissue and the entero-insular axis.

SUMMARY

Weight loss and calorie restriction partly explain the positive changes of glucose disposal. The multistep interaction of several factors at sites of insulin action, insulin secretion, adipose tissue and the entero-insular axis needs further investigation.