The effects of a low-carbohydrate diet on appetite: A randomized controlled trial

Impaired metabolic flexibility to fasting is associated with increased ad libitum energy intake in healthy adults

OBJECTIVE

We investigated how changes in 24-h respiratory exchange ratio (RER) and substrate oxidation during fasting versus an energy balance condition influence subsequent ad libitum food intake.

METHODS

Forty-four healthy, weight-stable volunteers (30 male and 14 female; mean [SD], age 39.3 [11.0] years; BMI 31.7 [8.3] kg/m2) underwent 24-h energy expenditure measurements in a respiratory chamber during energy balance (50% carbohydrate, 30% fat, and 20% protein) and 24-h fasting. Immediately after each chamber stay, participants were allowed 24-h ad libitum food intake from computerized vending machines.

RESULTS

Twenty-four-hour RER decreased by 9.4% (95% CI: -10.4% to -8.5%; p < 0.0001) during fasting compared to energy balance, reflecting a decrease in carbohydrate oxidation (mean [SD], -2.6 [0.8] MJ/day; p < 0.0001) and an increase in lipid oxidation (2.3 [0.9] MJ/day; p < 0.0001). Changes in 24-h RER and carbohydrate oxidation in response to fasting were correlated with the subsequent energy intake such that smaller decreases in fasting 24-h RER and carbohydrate oxidation, but not lipid oxidation, were associated with greater energy intake after fasting (r = 0.31, p = 0.04; r = 0.40, p = 0.007; and r = -0.27, p = 0.07, respectively).

CONCLUSIONS

Impaired metabolic flexibility to fasting, reflected by an inability to transition away from carbohydrate oxidation, is linked with increased energy intake.

Evidence-Based Strategies to Enhance Weight Management Programs for Adult Military Beneficiaries: A Narrative Review

INTRODUCTION

Overweight and obesity trends are on the rise among both civilian and military beneficiaries. The purpose of this narrative review was to evaluate nutrition, behavioral, lifestyle, pharmacotherapy, and alternative approaches to weight management (WM) among adults with a focus toward identifying gaps and evidence-based strategies that could support or enhance current and future WM programming among military adult beneficiaries.

MATERIALS AND METHODS

A trained research team identified publications (January 2013-January 2020) for abstract review using key search terms and inclusion criteria. Two independent researchers conducted both the abstract review and full-paper bias scoring using selected Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. All eligible studies were assessed for bias and categorized based on key themes. The study was registered in PROSPERO, the international prospective register of systematic reviews.

RESULTS

The research team identified 741 articles, with 278 meeting final inclusion criteria. The mean bias score was 7.5 ± 3.9 (score of 0-13; higher indicating fewer bias factors), with 64% scoring ≥9. Factors contributing to low bias included intervention compliance, dropout rate, and inability to blind participants. The most common published weight-loss interventions included a combination of therapies (59%), diet/supplement (17%), other approaches (12%), behavior change (7%), and exercise (6%). Themes identified to improve WM outcomes included leveraging technology, increasing intervention interactions, community support, emphasis on early weight loss, pharmacotherapy risk-benefit, enhanced behavioral component, resistance exercise, mindfulness, and benefits of quality-of-life measures.

CONCLUSIONS

Reviewers identified several validated tools and techniques to augment and update existing WM programming to improve health and weight outcomes. The review affirmed use of individualized dietary patterns and not a "one-size-fits-all approach" as well as incorporating more comprehensive and team-approached treatments to make the best use of tools and strategies to enhance outcomes.

Effects of a low-carbohydrate diet in adults with type 1 diabetes management: A single arm non-randomised clinical trial

Public interest in low-carbohydrate (LC) diets for type 1 diabetes (T1D) management has increased. This study compared the effects of a healthcare professional delivered LC diet compared to habitual diets higher in carbohydrates on clinical outcomes in adults with T1D. Twenty adults (18-70 yrs) with T1D (≥6 months duration) with suboptimal glycaemic control (HbA1c>7.0% or >53 mmol/mol) participated in a 16-week single arm within-participant, controlled intervention study involving a 4-week control period following their habitual diets (>150 g/day of carbohydrates) and a 12-week intervention period following a LC diet (25-75 g/day of carbohydrates) delivered remotely by a registered dietitian. Glycated haemoglobin (HbA1c -primary outcome), time in range (blood glucose: 3.5-10.0 mmol/L), frequency of hypoglycaemia (<3.5 mmol/L), total daily insulin, and quality of life were assessed before and after the control and intervention periods. Sixteen participants completed the study. During the intervention period, there were reductions in total dietary carbohydrate intake (214 to 63 g/day; P<0.001), HbA1c (7.7 to 7.1% or 61 to 54 mmol/mol; P = 0.003) and total daily insulin use (65 to 49 U/day; P<0.001), increased time spent in range (59 to 74%; P<0.001), and improved quality of life (P = 0.015), with no significant changes observed during the control period. Frequency of hypoglycaemia episodes did not differ across timepoints, and no episodes of ketoacidosis or other adverse events were reported during the intervention period. These preliminary findings suggest that a professionally supported LC diet may lead to improvements in markers of blood glucose control and quality of life with reduced exogenous insulin requirements and no evidence of increased hypoglycaemia or ketoacidosis risk in adults with T1D. Given the potential benefits of this intervention, larger, longer-term randomised controlled trials are warranted to confirm these findings. Trial Registration: https://www.anzctr.org.au/ACTRN12621000764831.aspx.

Influence of anti-obesity strategies on brain function in health and review: A review

The aim of this review was to investigate in the literature the application of strategies such as low carbohydrate diet (LCD), ketogenic diet (KD) and intermittent fasting (IF) and their effects on the CNS. We performed a narrative review of the literature. The search was specifically carried out in PubMed, selecting articles in English, which had the following keywords: obesity, central nervous system, low carb diet, ketogenic diet and intermittent fasting, using the narrative review methodology. The studies found show that the benefits of the LCD, KD and IF strategies, at the CNS level, have a strong influence on the mechanisms of hunger and satiety, as well as on the reduction of food reward and show improvement in memory and mood influenced by the interventions.

What predicts drug-free type 2 diabetes remission? Insights from an 8-year general practice service evaluation of a lower carbohydrate diet with weight loss

BACKGROUND

Type 2 diabetes (T2D) is often regarded as a progressive, lifelong disease requiring an increasing number of drugs. Sustained remission of T2D is now well established, but is not yet routinely practised. Norwood surgery has used a low-carbohydrate programme aiming to achieve remission since 2013.

METHODS

Advice on a lower carbohydrate diet and weight loss was offered routinely to people with T2D between 2013 and 2021, in a suburban practice with 9800 patients. Conventional 'one-to-one' GP consultations were used, supplemented by group consultations and personal phone calls as necessary. Those interested in participating were computer coded for ongoing audit to compare 'baseline' with 'latest follow-up' for relevant parameters.

RESULTS

The cohort who chose the low-carbohydrate approach (n=186) equalled 39% of the practice T2D register. After an average of 33 months median (IQR) weight fell from 97 (84-109) to 86 (76-99) kg, giving a mean (SD) weight loss of -10 (8.9)kg. Median (IQR) HbA1c fell from 63 (54-80) to 46 (42-53) mmol/mol. Remission of diabetes was achieved in 77% with T2D duration less than 1 year, falling to 20% for duration greater than 15 years. Overall, remission was achieved in 51% of the cohort. Mean LDL cholesterol decreased by 0.5 mmol/L, mean triglyceride by 0.9 mmol/L and mean systolic blood pressure by 12 mm Hg. There were major prescribing savings; average Norwood surgery spend was £4.94 per patient per year on drugs for diabetes compared with £11.30 for local practices. In the year ending January 2022, Norwood surgery spent £68 353 per year less than the area average.

CONCLUSIONS

A practical primary care-based method to achieve remission of T2D is described. A low-carbohydrate diet-based approach was able to achieve major weight loss with substantial health and financial benefit. It resulted in 20% of the entire practice T2D population achieving remission. It appears that T2D duration <1 year represents an important window of opportunity for achieving drug-free remission of diabetes. The approach can also give hope to those with poorly controlled T2D who may not achieve remission, this group had the greatest improvements in diabetic control as represented by HbA1c.

The effect of “moderately restricted carbohydrate” diet on gut microbiota composition and metabolic parameters in women with metabolic syndrome: a study protocol for a randomized controlled trial

Background

Metabolic syndrome (MetS) is a group of risk factors that increase the risk of death and a variety of chronic diseases. Recent studies have indicated that the imbalance of gut microbiota might contribute to development and progression of metabolic syndrome. Carbohydrate restriction in the diet has been proven to be one of the most effective methods in the management of metabolic syndrome, even in the absence of weight loss. However, no study has examined the effects of a carbohydrate-restricted diet on gut microbiota composition in metabolic syndrome patients. Thus, we will examine the effects of a “moderately restricted carbohydrate (MRC)” diet on gut microbiota, insulin resistance, and components of MetS among Iranian women. In addition, the stability of changes in dependent variables, including gut microbiota, will also be assessed.

Methods

This is a parallel randomized clinical trial in which 70 overweight or obese women aged 20–50 years with MetS will be randomly assigned to receive either MRC diet (42–45% carbohydrate, 35–40% fats) or a normal weight loss (NWL) diet (52–55% carbohydrate, 25–30% fats) for 3 months. Protein accounted for 15–17% of total energy in both diets. The quantity of gut microbiota including Firmicutes, Bacteroidetes, Bifidobacteria, Lactobacillus, Clostridium, Prevotella, Bacteroidetes, and Akkermansia muciniphila, as well as anthropometric, blood pressure, and metabolic parameters will be measured at study baseline and the end of trail. At the end of this phase, all participants will be placed on a weight maintenance diet for an additional 6 months. After following up study subjects in this duration, all dependent variables will be examined again to assess their stability over this period.

Discussion

To the best of our knowledge, this is the first randomized controlled trial investigating the effects of a moderately restricted carbohydrate diet on gut microbiota composition and several metabolic parameters during the weight loss and maintenance phases in women with MetS.

Trial registration

Iranian Registry of Clinical Trials (www.irct.ir, IRCT20210307050621N1). Registered on May 31, 2021.

The role of cereal soluble fiber in the beneficial modulation of glycometabolic gastrointestinal hormones

According to cohort studies, cereal fiber, and whole-grain products might decrease risk for type 2 diabetes (T2DM), inflammatory processes, cancer, and cardiovascular diseases. These associations, mainly affect insoluble, but not soluble cereal fiber. In intervention studies, soluble fiber elicit anti-hyperglycemic and anti-inflammatory short-term effects, partially explained by fermentation to short-chain fatty acids, which acutely counteract insulin resistance and inflammation. ß-glucans lower cholesterol levels and possibly reduce liver fat. Long-term benefits are not yet shown, maybe caused by T2DM heterogeneity, as insulin resistance and fatty liver disease - the glycometabolic points of action of soluble cereal fiber - are not present in every patient. Thus, only some patients might be susceptive to fiber. Also, incretin action in response to fiber could be a relevant factor for variable effects. Thus, this review aims to summarize the current knowledge from human studies on the impact of soluble cereal fiber on glycometabolic gastrointestinal hormones. Effects on GLP-1 appear to be highly contradictory, while these fibers might lower GIP and ghrelin, and increase PYY and CCK. Even though previous results of specific trials support a glycometabolic benefit of soluble fiber, larger acute, and long-term mechanistic studies are needed in order to corroborate the results.

The challenge of weight loss maintenance in obesity: a review of the evidence on the best strategies available

Long-term weight loss maintenance represents a big challenge for the management of obesity. This narrative review aims to provide an overview of the main endocrine mechanisms involved in weight regain in subjects with obesity and to review the current evidence on the best lifestyle approaches, including diet and physical activity. Weight regain after weight loss occurs in about 50% of subjects with obesity in the absence of lifestyle changes. The primary endocrine mechanism responsible for weight regain involves the brain-gut axis, which encourages food intake and thus weight regain through the secretion and action of several gastrointestinal hormones, such as ghrelin, leptin and cholecystokinin. Several evidence reported changes of secretion of these hormones during weight loss and weight loss maintenance programs. Endurance training is the most effective physical activity to lose and keep weight loss; the association of endurance with resistance training is recommended for remodelling body shape.

Effects of a Low-Carbohydrate Dietary Intervention on Hemoglobin A1c: A Randomized Clinical Trial

IMPORTANCE

Low-carbohydrate diets decrease hemoglobin A1c (HbA1c) among patients with type 2 diabetes at least as much as low-fat diets. However, evidence on the effects of low-carbohydrate diets on HbA1c among individuals with HbA1c in the range of prediabetes to diabetes not treated by diabetes medications is limited.

OBJECTIVE

To study the effect of a behavioral intervention promoting a low-carbohydrate diet compared with usual diet on 6-month changes in HbA1c among individuals with elevated untreated HbA1c.

DESIGN, SETTING, AND PARTICIPANTS

This 6-month randomized clinical trial with 2 parallel groups was conducted from September 2018 to June 2021 at an academic medical center in New Orleans, Louisiana. Laboratory analysts were blinded to assignment. Participants were aged 40 to 70 years with untreated HbA1c of 6.0% to 6.9% (42-52 mmol/mol). Data analysis was performed from November 2021 to September 2022.

INTERVENTIONS

Participants were randomized to a low-carbohydrate diet intervention (target <40 net grams of carbohydrates during the first 3 months; <60 net grams for months 3 to 6) or usual diet. The low-carbohydrate diet group received dietary counseling.

MAIN OUTCOMES AND MEASURES

Six-month change in HbA1c was the primary outcome. Outcomes were measured at 0, 3, and 6 months.

RESULTS

Of 2722 prescreened participants, 962 underwent screening, and 150 were enrolled (mean [SD] age, 58.9 [7.9] years; 108 women [72%]; 88 Black participants [59%]) and randomized to either the low-carbohydrate diet intervention (75 participants) or usual diet (75 participants) group. Six-month data were collected on 142 participants (95%). Mean (SD) HbA1c was 6.16% (0.30%) at baseline. Compared with the usual diet group, the low-carbohydrate diet intervention group had significantly greater 6-month reductions in HbA1c (net difference, -0.23%; 95% CI, -0.32% to -0.14%; P < .001), fasting plasma glucose (-10.3 mg/dL; 95% CI, -15.6 to -4.9 mg/dL; P < .001), and body weight (-5.9 kg; 95% CI, -7.4 to -4.4 kg; P < .001).

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, a low-carbohydrate dietary intervention led to improvements in glycemia in individuals with elevated HbA1c not taking glucose-lowering medication, but the study was unable to evaluate its effects independently of weight loss. This diet, if sustained, might be a useful dietary approach for preventing and treating type 2 diabetes, but more research is needed.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03675360.

Eggs Improve Plasma Biomarkers in Patients with Metabolic Syndrome Following a Plant-Based Diet-A Randomized Crossover Study

Plant-based (PB) diets are considered a healthy dietary pattern; however, eggs are not always included in this dietary regime. We hypothesized that the addition of two eggs per day would increase HDL cholesterol as well as plasma lutein, zeaxanthin and choline in individuals with metabolic syndrome (MetS). In this randomized controlled crossover intervention, we recruited 30 participants (49.3 ± 8 y) with MetS who followed a PB diet for 13 weeks. A registered dietitian advised all subjects on food selection and followed them through the intervention to ensure compliance. Participants underwent a 2-week washout with no eggs or spinach (a source of dietary lutein and zeaxanthin) and were randomly allocated to consume spinach (70 g) with either two eggs (EGG) or the equivalent amount of egg substitute (SUB) for breakfast for 4 weeks. After a 3-week washout, they were allocated the alternate breakfast. A total of 24 participants (13 women/11 men) finished the intervention. Plasma lipids, glucose, insulin, anthropometrics, plasma lutein, zeaxanthin, choline and trimethylamine oxide (TMAO) were assessed at baseline and the end of each intervention. When we compared individuals consuming the EGG versus the SUB breakfast, we observed a lower body weight (p < 0.02) and a higher HDL cholesterol (p < 0.025) after the EGG diet. There were no differences in plasma LDL cholesterol, triglycerides, glucose, insulin, or blood pressure. The number of large HDL particles measured by NMR was higher after EGG (p < 0.01) as compared to SUB. Plasma choline was higher in both treatments (p < 0.01) compared to baseline (8.3 ± 2.1 μmol/L). However, plasma choline values were higher in EGG (10.54 ± 2.8 μmol/L) compared to SUB (9.47 ± 2.7 μmol/L) p < 0.025. Both breakfasts increased plasma lutein compared to baseline (p < 0.01), while plasma zeaxanthin was only increased in the egg intervention (p < 0.01). These results indicate that consuming a plant-based diet in combination with whole eggs increases plasma HDL cholesterol, choline and zeaxanthin, important biomarkers in subjects with MetS.

Long Term Weight Loss Diets and Obesity Indices: Results of a Network Meta-Analysis

Background

Scientists have been investigating efficient interventions to prevent and manage obesity. This network meta-analysis (NMA) compared the effect of different diets [moderate macronutrients (MMs), low fat/high carbohydrate (LFHC), high fat/low carbohydrate (HFLC), and usual diet (UD)] on weight, body mass index (BMI), and waist circumference (WC) changes at ≥12 months.

Methods

We searched Medline, Embase, PubMed databases, and the Cochrane Library. We systematically assessed randomized controlled trials (RCTs) evaluating dietary interventions on adults (mean BMI ≥ 25 kg/m²) receiving active dietary counseling for ≥12 months. We pooled the data using a random-effect NMA. We assessed the quality of the included RCTs using the Cochrane risk of bias (ROB) tool.

Results

We included 36 trials, 14 of which compared HFLC with MM diets. Compared with UD, all diets were associated with a significant weight loss (WL) at ≥12 months, HFLC [mean difference in kg (95% CI): −5.5 (−7.6; −3.4)], LFHC [−5.0 (−7.1; −2.9)] and MM [−4.7 (−6.8; −2.7)]. HFLC, compared with MM diet, was associated with a slightly higher WL (of −0.77 kg) and drop in BMI (of −0.36 kg/m²), while no significant difference was detected in other dietary comparisons. WC was lower with all diets compared to UD, with no significant difference across specific diets. There was no significant interaction of the results with the pre-specified sub-groups. The ROB was moderate to high, mostly related to unclear allocation concealment, high dropout rate and unclear or lack of blinding of participants, providers, and outcome assessors.

Conclusion

Dietary interventions extending over ≥12 months are superior to UD in inducing weight, BMI and WC loss. HFLC might be associated with a slightly higher WL compared with MM diets.

Systematic Trial Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=103116, PROSPERO (CRD42018103116).

The low-carbohydrate-diet score is associated with resting metabolic rate: an epidemiologic study among Iranian adults

Purpose

Low-carbohydrate diet (LCD) has been used for weight loss and preventing obesity, but the association of adherence to LCD and resting metabolic rate (RMR) has not been investigated. This study aimed to investigate the association between the low-carbohydrate-diet score (LCDS) and RMR among Iranian adults.

Methods

This cross-sectional study was conducted on 270 Iranian adults 18-70 y of age. To assess dietary intakes, participants completed a validated food frequency questionnaire. The LCDS was calculated based on carbohydrate, protein and fat intake, expressed as a percentage of energy. The higher score indicates the lower carbohydrate and the higher protein and fat intake. RMR was measured by indirect calorimetry after an overnight fast.

Results

Multivariate-adjusted means showed that RMR significantly increased across tertiles (p = 0.041). However, there were no significant differences in the mean of fat mass (FM) and fat-free mass (FFM) across tertiles of LCDS (p = 0.986 and p = 0.621, respectively). Also LCDS and RMR (r = 0.14, p = 0.021) were found to be correlated, but LCDS and FFM (r = 0.06, p = 0.323), FM (r = -0.05, p = 0.412), had no statistically significant correlation. RMR had a significant positive association with LCDs in the crude model (β = 18.81, 95% CI: 2.55, 35.07, P = 0.024). Moreover, after controlling for covariates this association changed to non-significant (β = -0.14, 95% CI: -7.05, 19.25, P = 0.03).

Conclusion

Adherence to diets lower in carbohydrates and higher in fat and protein were associated with higher RMR. Further studies with a larger sample size are needed to confirm these findings.

Effects of modified-Paleo and moderate-carbohydrate diets on body composition, serum levels of hepatokines and adipocytokines, and flow cytometric analysis of endothelial microparticles in adults with metabolic syndrome: a study protocol for a randomized clinical trial

Background

Metabolic syndrome is a combination of metabolic risk factors causing a pathological condition that increases the risk of non-communicable diseases, such as diabetes and cardiovascular diseases. A variety of dietary approaches have been examined to halt this rapid trend; however, the effects of modified-Paleo diet and medium-carbohydrate diet on inflammation, adipokines, hepatokines, and the profile of endothelial microparticles in individuals with metabolic syndrome have not been investigated in detail. The present study is designed to examine the effect of modified-Paleo and moderate-carbohydrate diet with two delivery modes: “fixed diet plan” vs “calorie counting” on weight, body composition, serum levels of some hepatokines and adipocytokines, and flow cytometric analysis of endothelial microparticles in adults with metabolic syndrome.

Methods

Eighty metabolic syndrome patients will be recruited in this study. They will be randomly allocated to one of the following 4 groups: (1) receiving a modified-Paleo diet with calorie counting, (2) receiving a modified-Paleo diet with a fixed diet plan, (3) receiving a medium-carbohydrate diet with calorie counting, and (4) receiving a medium-carbohydrate diet with a fixed diet plan for 10 weeks. Weight, height, waist circumference, and body composition will be assessed at the study baseline and at the end of the trial. Serum insulin, asprosin, chemerin, FGF-21, CTRP-1, PYY, ghrelin, plasma EMPs (CD31+/CD42b− and CD144+/CD42b−), lipid profile, glycemic indices, hs-CRP, leptin, vitamin C, creatinine and satiety, hunger, fullness, and desire to eat (via visual analog scales) will be measured at the study baseline and at the end of the trial. Insulin resistance and insulin sensitivity will be determined using the HOMA-IR and QUICKI equations.

Discussion

To the best of our knowledge, this is the first randomized controlled trial that will determine the effect of modified-Paleo and moderate-carbohydrate diet on weight, body composition, serum levels of some hepatokines and adipocytokines, and the profile of EMPs in adults with metabolic syndrome. Moreover, the effects of different diet delivery modes, including “fixed diet plan” and “calorie counting” will also be analyzed. The results of this trial can provide clinical witnesses on the effectiveness of carbohydrate-restricted diets in ameliorating metabolic status and prevent the development of chronic diseases.

Trial registration

Iranian Registry of Clinical Trials IRCT2016121925267N4. Registered on 26 July 2017

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05612-y.

Benefits of Low Carbohydrate Diets: a Settled Question or Still Controversial?

PURPOSE OF REVIEW

The purpose of this review was to provide an update on the available data on the benefits of low-carbohydrate (low-carb) diets for weight management and type 2 diabetes (T2DM) and determine if low-carb diets were a settled question or still controversial.

RECENT FINDINGS

Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials. Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both. There are numerous challenges in trying to draw clear conclusions about efficacy and effectiveness. Short-term vs. long-term effects can differ, which is likely impacted by adherence. Adherence is very different between metabolic chamber or feeding studies vs. free-living. Body weight alone is a crude measure that fails to capture potentially important differences in lean-mass, fat-mass, and body water. Benefits for glycemic control need to be balanced with impacts on non-glycemic outcomes such as LDL-cholesterol, the microbiome, and inflammation. It is important to differentiate between low-carb and very-low carbohydrate diets (VLCD). To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM. Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD. Some of the recent, better studies highlighted in this review suggest strategies for resolving these controversies.

Low-carbohydrate diets lead to greater weight loss and better glucose homeostasis than exercise: a randomized clinical trial

Lifestyle interventions, including dietary adjustments and exercise, are important for obesity management. This study enrolled adults with overweight or obesity to explore whether either low-carbohydrate diet (LCD) or exercise is more effective in metabolism improvement. Forty-five eligible subjects were randomly divided into an LCD group (n = 22) and an exercise group (EX, n = 23). The subjects either adopted LCD (carbohydrate intake < 50 g/day) or performed moderate-to-vigorous exercise (⩾ 30 min/day) for 3 weeks. After the interventions, LCD led to a larger weight loss than EX ( - 3.56 ± 0.37 kg vs. - 1.24 ± 0.39 kg, P < 0.001), as well as a larger reduction in fat mass ( - 2.10 ± 0.18 kg vs. - 1.25 ± 0.24 kg, P = 0.007) and waist circumference ( - 5.25 ± 0.52 cm vs. - 3.45 ± 0.38 cm, P = 0.008). Both interventions reduced visceral and subcutaneous fat and improved liver steatosis and insulin resistance. Triglycerides decreased in both two groups, whereas low-density lipoprotein cholesterol increased in the LCD group but decreased in the EX group. Various glycemic parameters, including serum glycated albumin, mean sensor glucose, coefficient of variability (CV), and largest amplitude of glycemic excursions, substantially declined in the LCD group. Only CV slightly decreased after exercise. This pilot study suggested that the effects of LCD and exercise are similar in alleviating liver steatosis and insulin resistance. Compared with exercise, LCD might be more efficient for weight loss and glucose homeostasis in people with obesity.

A High-Protein, Low Glycemic Index Diet Suppresses Hunger but Not Weight Regain After Weight Loss: Results From a Large, 3-Years Randomized Trial (PREVIEW)

Background: Previous studies have shown an increase in hunger during weight-loss maintenance (WLM) after diet-induced weight loss. Whether a combination of a higher protein, lower glycemic index (GI) diet and physical activity (PA) can counteract this change remains unclear. Aim: To compare the long-term effects of two diets [high protein (HP)-low GI vs. moderate protein (MP)-moderate GI] and two PA programs [high intensity (HI) vs. moderate intensity (MI)] on subjective appetite sensations during WLM after ≥8% weight loss (WL). Methods: Data derived from the 3-years PREVIEW randomized intervention study. An 8-weeks WL phase using a low-energy diet was followed by a 148-weeks randomized WLM phase. For the WLM phase, participants were assigned to one of the four groups: HP-MI, HP-HI, MP-MI, and MP-HI. Available data from 2,223 participants with overweight or obesity (68% women; BMI ≥ 25 kg/m²). Appetite sensations including satiety, hunger, desire to eat, and desire to eat something sweet during the two phases (at 0, 8 weeks and 26, 52, 104, and 156 weeks) were assessed based on the recall of feelings during the previous week using visual analogue scales. Differences in changes in appetite sensations from baseline between the groups were determined using linear mixed models with repeated measures. Results: There was no significant diet × PA interaction. From 52 weeks onwards, decreases in hunger were significantly greater in HP-low GI than MP-moderate GI (P _{time × diet} = 0.018, P _dietgroup = 0.021). Although there was no difference in weight regain between the diet groups (P _{time × diet} = 0.630), hunger and satiety ratings correlated with changes in body weight at most timepoints. There were no significant differences in appetite sensations between the two PA groups. Decreases in hunger ratings were greater at 52 and 104 weeks in HP-HI vs. MP-HI, and greater at 104 and 156 weeks in HP-HI vs. MP-MI. Conclusions: This is the first long-term, large-scale randomized intervention to report that a HP-low GI diet was superior in preventing an increase in hunger, but not weight regain, during 3-years WLM compared with a MP-moderate GI diet. Similarly, HP-HI outperformed MP-HI in suppressing hunger. The role of exercise intensity requires further investigation. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT01777893.

Weight loss, hypertension and mental well-being improvements during COVID-19 with a multicomponent health promotion programme on Zoom: a service evaluation in primary care

Background

Obesity is a risk factor for complications from SARS-CoV-2 infection, increasing the need for effective weight management measures in primary care. However, in the UK, COVID-19 restrictions have hampered primary care weight management referral and delivery, and COVID-19 related weight gain has been reported. The present study evaluated outcomes from a multicomponent weight loss and health promotion programme in UK primary care, delivered remotely due to COVID-19 restrictions.

Method

Patients with obesity, type 2 diabetes or pre-diabetes attended six 90 min sessions over 10 weeks on Zoom. The dietary component comprised a low-carbohydrate ‘real food’ approach, augmented with education on physical activity, intermittent fasting, gut health, stress management, sleep and behaviour change. Anthropometric and cardiometabolic data were self-reported. Mental well-being was assessed with the Warwick Edinburgh Mental Wellbeing Scale. Subjective outcomes and participant feedback about the programme were collected with an anonymous online survey.

Results

Twenty participants completed the programme. Weight loss and improvements in body mass index, waist circumference, systolic and diastolic blood pressure and mental well-being achieved statistical and clinical significance. Mean weight loss (5.8 kg) represented a 6.5% weight loss. Participants’ subjective outcomes included weight loss without hunger (67%) and increased confidence in their ability to improve health (83%). All participants reported the usage of Zoom to access the programme as acceptable with 83% reporting it worked well.

Conclusion

A multicomponent weight loss and health promotion programme with a low-carbohydrate dietary component, clinically and statistically significantly improved health outcomes including weight status, blood pressure and mental well-being in a group of primary care patients when delivered remotely. Further research is warranted.

Nutritional Ketosis as a Potential Treatment for Alcohol Use Disorder

Alcohol use disorder (AUD) is a chronic, relapsing brain disorder, characterized by compulsive alcohol seeking and disrupted brain function. In individuals with AUD, abstinence from alcohol often precipitates withdrawal symptoms than can be life threatening. Here, we review evidence for nutritional ketosis as a potential means to reduce withdrawal and alcohol craving. We also review the underlying mechanisms of action of ketosis. Several findings suggest that during alcohol intoxication there is a shift from glucose to acetate metabolism that is enhanced in individuals with AUD. During withdrawal, there is a decline in acetate levels that can result in an energy deficit and could contribute to neurotoxicity. A ketogenic diet or ingestion of a ketone ester elevates ketone bodies (acetoacetate, β-hydroxybutyrate and acetone) in plasma and brain, resulting in nutritional ketosis. These effects have been shown to reduce alcohol withdrawal symptoms, alcohol craving, and alcohol consumption in both preclinical and clinical studies. Thus, nutritional ketosis may represent a unique treatment option for AUD: namely, a nutritional intervention that could be used alone or to augment the effects of medications.

Current Evidence Regarding Low-carb Diets for The Metabolic Control of Type-2 Diabetes

The management of diabetes requires a medical nutrition therapy as an essential part of this treatment. There should be no "one-size-fits-all" eating pattern for different patient´s profiles with diabetes. It is clinically complex to suggest an ideal percentage of calories from carbohydrates, protein and lipids recommended for all patients with diabetes. Among the eating patterns that have shown beneficial effects on metabolic control of patients with type 2 diabetes is the lowcarb diet, since the carbohydrate ingestion is viewed as the most important determinant of postprandial glucose and insulin response. In this context, theoretically, it could make sense to reduce the daily amount of carbohydrates ingested, to achieve lower levels of HbA1c. There could be risks associated to this approach. The adherence to a low-carb diet is here also discussed. This narrative review shows on the current evidence for answering these questions regarding low-carb diet as a possible alternative eating pattern for type 2 diabetes.

Dietary Management of Obesity: A Review of the Evidence

Obesity is a multi-factorial disease and its prevention and management require knowledge of the complex interactions underlying it and adopting a whole system approach that addresses obesogenic environments within country specific contexts. The pathophysiology behind obesity involves a myriad of genetic, epigenetic, physiological, and macroenvironmental factors that drive food intake and appetite and increase the obesity risk for susceptible individuals. Metabolically, food intake and appetite are regulated via intricate processes and feedback systems between the brain, gastrointestinal system, adipose and endocrine tissues that aim to maintain body weight and energy homeostasis but are also responsive to environmental cues that may trigger overconsumption of food beyond homeostatic needs. Under restricted caloric intake conditions such as dieting, these processes elicit compensatory metabolic mechanisms that promote energy intake and weight regain, posing great challenges to diet adherence and weight loss attempts. To mitigate these responses and enhance diet adherence and weight loss, different dietary strategies have been suggested in the literature based on their differential effects on satiety and metabolism. In this review article, we offer an overview of the literature on obesity and its underlying pathological mechanisms, and we present an evidence based comparative analysis of the effects of different popular dietary strategies on weight loss, metabolic responses and diet adherence in obesity.

Low carbohydrate ketogenic therapy as a metabolic treatment for binge eating and ultraprocessed food addiction

PURPOSE OF REVIEW

The aim of this study was to highlight the recent advancements and future directions for potential use of a low carbohydrate ketogenic dietary approach to treat binge eating and ultraprocessed food addiction. Herein, we explore proposed mechanisms of why a diet low in refined carbohydrates, processed sugar and higher fat content may be helpful in alleviating symptoms.

RECENT FINDINGS

Emerging evidence suggests there may be a metabolic role in development of maladaptive eating. These findings broaden our understanding of eating psychopathology causes. Ultraprocessed, refined or high glycemic index carbohydrates are a possible trigger mediating neurochemical responses similar to addiction. The carbohydrate-insulin model of obesity supports observations of these foods triggering abnormal blood sugar and insulin spikes subsequently leading to changes in metabolic and neurobiological signaling. This results in overeating symptoms and hunger exacerbation, which differs from observed effects of healthy fat consumption and lack of similar insulin spikes. As supported in recent case series, significantly reducing or abstaining from these addictive-like ultraprocessed foods and highly refined carbohydrates could be considered a treatment approach.

SUMMARY

The current review highlights recent and pertinent evidence with respect to theoretical and practical application of low carbohydrate ketogenic therapeutic approaches for ultraprocessed food addiction and binge eating symptoms. VIDEO ABSTRACT:.

Effects of Dietary Carbohydrate Content on Circulating Metabolic Fuel Availability in the Postprandial State

Context

According to the carbohydrate-insulin model of obesity, an elevated insulin-to-glucagon ratio in response to a high-carbohydrate diet directs metabolic fuels toward storage, resulting in lower circulating energy.

Objective

To determine differences in total circulating energy post-meal related to dietary carbohydrate.

Design

Ancillary study within the Framingham State Food Study.

Setting

University community.

Participants

29 adults (aged 20 to 65 years) with overweight or obesity (body mass index ≥25 kg/m²)

Intervention

After achieving 10% to 14% weight loss on a run-in diet, participants were randomized to weight-loss-maintenance test diets varying in carbohydrate content (high-carbohydrate, 60% of total energy, n = 11; moderate-carbohydrate, 40%, n = 8; low-carbohydrate, 20%, n = 10) and controlled for protein (20%). During 24-hour metabolic ward admissions between 10 and 15 weeks on the test diets, metabolic fuels and hormones were measured.

Main Outcome Measure

Energy availability (EA) based on energy content of blood glucose, beta-hydroxybutyrate, and free fatty acids, in the late postprandial period (180 to 300 minutes). Insulin at 30 minutes into the test meal (Meal Insulin-30) was measured as an effect modifier.

Results

Insulin-to-glucagon ratio was 7-fold higher in participants on the high- vs low-carbohydrate diet (2.5 and 0.36, respectively). Late postprandial EA was 0.58 kcal/L lower on the high- vs low-carbohydrate diet (P < 0.0001), primarily related to suppression of free fatty acids. Early postprandial EA (30 to 180 minutes) declined fastest in the high-carbohydrate group, and Meal Insulin-30 modified this diet effect.

Conclusions

During weight-loss maintenance on a high-carbohydrate diet, late postprandial EA is reduced, consistent with the carbohydrate-insulin model.

Low-Carbohydrate Diets in the Management of Obesity and Type 2 Diabetes: A Review from Clinicians Using the Approach in Practice

Low-carbohydrate diets are increasingly used to help patients with obesity and type 2 diabetes. We sought to provide an overview of the evidence for this treatment approach, considering the epidemiology and pathophysiology of obesity and diabetes in terms of carbohydrate excess. We describe the mechanistic basis for the clinical benefits associated with nutritional ketosis and identify areas of practice where the evidence base could be improved. We summarize the key principles which inform our approach to treating patients with low-carbohydrate diets. The scientific controversy relating to these diets is real but is consistent with the known challenges of any dietary interventions and also the limitations of nutritional epidemiology. Secondly, notwithstanding any controversy, international guidelines now recognize the validity and endorse the use of these diets as a therapeutic nutritional approach, in appropriate patients. Thirdly, we have found that early de-prescription of diabetes medications is essential, in particular insulin, sulphonylureas, and sodium-glucose cotransporter (SGLT2) inhibitors. Fourthly, we encourage patients to eat ad libitum to satiety, rather than calorie counting per se. Furthermore, we monitor cardiovascular risk factors frequently, as with all patients with obesity or diabetes, but we do not necessarily consider an increase in low-density lipoprotein (LDL)-cholesterol as an absolute indication to stop these diets, as this is usually related to large LDL particles, which are not associated with increased cardiovascular risk. In the absence of large randomized controlled trials with cardiovascular and other hard endpoints, adopting a low-carbohydrate diet is a legitimate and potentially effective treatment option for patients with diabetes or obesity.

Low and reduced carbohydrate diets: challenges and opportunities for type 2 diabetes management and prevention

Low-carbohydrate diets (LCD) have been promoted for weight control and type 2 diabetes (T2D) management, based on an emerging body of evidence, including meta-analyses with an indication of publication bias. Proposed definitions vary between 50 and 130 g/d, or <10 and <40 % of energy from carbohydrate, with no consensus on LCD compositional criteria. LCD are usually followed with limited consideration for other macronutrients in the overall diet composition, introducing variance in the constituent foods and in metabolic responses. For weight management, extensive evidence supports LCD as a valid weight loss treatment, up to 1-2 years. Solely lowering carbohydrate intake does not, in the medium/long term, reduce HbA1c for T2D prevention or treatment, as many mechanisms interplay. Under controlled feeding conditions, LCD are not physiologically or clinically superior to diets with higher carbohydrates for weight-loss, fat loss, energy expenditure or glycaemic outcomes; indeed, all metabolic improvements require weight loss. Long-term evidence also links the LCD pattern to increased CVD risks and mortality. LCD can lead to micronutrient deficiencies and increased LDL-cholesterol, depending on food selection to replace carbohydrates. Evidence is limited but promising regarding food choices/sources to replace high-carbohydrate foods that may alleviate the negative effects of LCD, demanding further insight into the dietary practice of medium to long term LCD followers. Long-term, high-quality studies of LCD with different food sources (animal and/or plant origins) are needed, aiming for clinical endpoints (T2D incidence and remission, cardiovascular events, mortality). Ensuring micronutrient adequacy by food selection or supplementation should be considered for people who wish to pursue long-term LCD.

Treating binge eating and food addiction symptoms with low-carbohydrate Ketogenic diets: a case series

BACKGROUND

Many patients with obesity and comorbid binge eating symptoms present with the desire to lose weight. Although some studies suggest that dietary restriction can exacerbate binge eating, others show dietary restriction is associated with significant reductions in binge eating. The effect of a particular type of dieting on binge eating, the ketogenic diet (a high fat, moderate protein, very low carbohydrate diet), is not known.

CASE PRESENTATIONS

We report on the feasibility of a low-carbohydrate ketogenic diet initiated by three patients (age 54, 34, and 63) with obesity (average BMI 43.5 kg/m2) with comorbid binge eating and food addiction symptoms. All patients tolerated following the ketogenic diet (macronutrient proportion 10% carbohydrate, 30% protein, and 60% fat; at least 5040 kJ) for the prescribed period (e.g., 6-7 months) and none reported any major adverse effects. Patients reported significant reductions in binge eating episodes and food addiction symptoms including cravings and lack of control as measured by the Binge-Eating Scale, Yale Food Addiction Scale, or Yale-Brown Obsessive-Compulsive Scale modified for Binge Eating, depending on the case. Additionally, the patients lost a range of 10-24% of their body weight. Participants reported maintenance of treatment gains (with respect to weight, binge eating, and food addiction symptoms) to date of up to 9-17 months after initiation and continued adherence to diet.

CONCLUSIONS

Although the absence of control cases precludes conclusions regarding the specific role of ketogenic diets versus other forms of dietary restriction, this is the first report to demonstrate the feasibility of prescribing a ketogenic diet for patients with obesity who report binge eating and food addiction symptoms. Further research should seek to reproduce the observed effects in controlled trials as well as to explore potential etiologies.

Alternate day fasting combined with a low-carbohydrate diet for weight loss, weight maintenance, and metabolic disease risk reduction

OBJECTIVE

Alternate day fasting (ADF) is a popular weight loss regimen. Whether carbohydrate restriction can enhance the weight loss achieved with ADF remains unclear. Accordingly, this study examined the effect of ADF combined with a low-carbohydrate diet on body weight and metabolic disease risk factors.

METHODS

Adults with obesity (n = 31) participated in ADF (600 kcal "fast day" alternated with an ad libitum "feast day") with a low-carbohydrate background diet (30% carbohydrates, 35% protein, and 35% fat). The 6-month trial consisted of a 3-month weight loss period followed by a 3-month weight maintenance period.

RESULTS

Body weight decreased (-5.5 ± 0.5%; P < .001) during the weight loss period (month 0-3) but remained stable (P = .57) during the weight maintenance period (month 4-6). Net weight loss by month 6 was -6.3 ± 1.0%. Fat mass was reduced (P < .01) by month 6, while lean mass and visceral fat mass remained unchanged. Total cholesterol and low-density lipoprotein (LDL) cholesterol levels decreased (P < .05) by -6 ± 2% and - 8 ± 3%, respectively, by month 6. Systolic blood pressure was also reduced (P = .03) by -7 ± 3 mm Hg. Fasting insulin decreased (P = .03) by -24 ± 8% by month 6 relative to baseline. High-density lipoprotein (HDL) cholesterol, triglycerides, diastolic blood pressure, heart rate, fasting glucose, homeostatic model assessment of insulin resistance (HOMA-IR), and haemoglobin A1C (HbA1c) remained unchanged.

CONCLUSIONS

These findings suggest that ADF combined with a low-carbohydrate diet is effective for weight loss, weight maintenance, and improving certain metabolic disease risk factors such as LDL cholesterol, blood pressure, and fasting insulin. While these preliminary findings are promising, they still require confirmation by a randomized control trial.

Low Carbohydrate and Low-Fat Diets: What We Don't Know and Why we Should Know It

In the 1940s, the diet-heart hypothesis proposed that high dietary saturated fat and cholesterol intake promoted coronary heart disease in "at-risk" individuals. This hypothesis prompted federal recommendations for a low-fat diet for "high risk" patients and as a preventive health measure for everyone except infants. The low carbohydrate diet, first used to treat type 1 diabetes, became a popular obesity therapy with the Atkins diet in the 1970s. Its predicted effectiveness was based largely on the hypothesis that insulin is the causa prima of weight gain and regain via hyperphagia and hypometabolism during and after weight reduction, and therefore reduced carbohydrate intake would promote and sustain weight loss. Based on literature reviews, there are insufficient randomized controlled inpatient studies examining the physiological significance of the mechanisms proposed to support one over the other. Outpatient studies can be confounded by poor diet compliance such that the quality and quantity of the energy intake cannot be ascertained. Many studies also fail to separate macronutrient quantity from quality. Overall, there is no conclusive evidence that the degree of weight loss or the duration of reduced weight maintenance are significantly affected by dietary macronutrient quantity beyond effects attributable to caloric intake. Further work is needed.

Review of current evidence and clinical recommendations on the effects of low-carbohydrate and very-low-carbohydrate (including ketogenic) diets for the management of body weight and other cardiometabolic risk factors: A scientific statement from the National Lipid Association Nutrition and Lifestyle Task Force

Historically, low-carbohydrate (CHO) and very-low-CHO diets have been used for weight loss. Recently, these diets have been promoted for type 2 diabetes (T2D) management. This scientific statement provides a comprehensive review of the current evidence base available from recent systematic reviews and meta-analyses on the effects of low-CHO and very-low-CHO diets on body weight, lipoprotein lipids, glycemic control, and other cardiometabolic risk factors. In addition, evidence on emerging risk factors and potential safety concerns of low-CHO and very-low-CHO diets, especially for high-risk individuals, such as those with genetic lipid disorders, was reviewed. Based on the evidence reviewed, low-CHO and very-low-CHO diets are not superior to other dietary approaches for weight loss. These diets may have advantages related to appetite control, triglyceride reduction, and reduction in the use of medication in T2D management. The evidence reviewed showed mixed effects on low-density lipoprotein cholesterol levels with some studies showing an increase. There was no clear evidence for advantages regarding effects on other cardiometabolic risk markers. Minimal data are available regarding long-term (>2 years) efficacy and safety. Clinicians are encouraged to consider the evidence discussed in this scientific statement when counseling patients on the use of low-CHO and very-low-CHO diets.

Dietary modifications for weight loss and weight loss maintenance

Worldwide obesity rates remain at a rise, and to treat obesity is at the top of the global public health agenda. In 2013, the AHA/ACC/TOS obesity management guidelines were published, in essence suggesting that any dietary scheme seems to be effective for weight loss, as long as it can induce a sustainable energy deficit. In the present review, we update and critically discuss available information regarding dietary modifications for weight loss and weight loss maintenance, published after the 2013 guidelines. Regarding weight loss, we found no proof to support that a single dietary scheme, be it nutrient-, food group- or dietary pattern- based, is more efficacious of the other for achieving weight loss. For weight loss maintenance, published interventions point towards the same direction, although inconclusively. Most research explores the effect of weight loss regimes on weight loss maintenance and not the effect of the diet during weight loss maintenance, and this literature gap should be more thoroughly investigated.

A low-carbohydrate survey: Evidence for sustainable metabolic syndrome reversal

Background: Metabolic syndrome has become a significant problem, with the American Diabetes Association estimating the cost of diabetes and pre-diabetes in the United States alone to be $322 billion per year. Numerous clinical trials have demonstrated the efficacy of low-carbohydrate diets in reversing metabolic syndrome and its associated disorders.Aim: This study was designed to examine how voluntary adherents to a low-carbohydrate diet rate its effectiveness and sustainability using an online survey.Setting and methods: The 57-question survey was administered online and shared internationally via social media and ‘low-carb’ communities. Where appropriate, chi-squared tests and paired t-tests were used to analyse the responses.Results: There were 1580 respondents. The majority of respondents had consumed less than 100 g of carbohydrates per day for over a year, typically for reasons of weight loss or disease management. There was a reported decrease in waist circumference and weight with a simultaneous decrease in hunger and increase in energy level. Of those who provided laboratory values, the majority saw improvements in their HbA1c, blood glucose measurements, and lipid panel results. There was a reduction in usage of various medications, and 25% reported medication cost savings, with average monthly savings of $288 for those respondents. In particular, the usage of pain relievers and anti-inflammatories dropped with a simultaneous decreased rating of pain and increase in mobility.Conclusion: We conclude that low-carbohydrate diets are a sustainable method of metabolic syndrome reversal in a community setting.

A 12-week low-carbohydrate, high-fat diet improves metabolic health outcomes over a control diet in a randomised controlled trial with overweight defence force personnel

Overweight, obesity, and poor health is becoming a global concern for defence force personnel. Conventional nutrition guidelines are being questioned for their efficacy in achieving optimal body composition and long-term health. This study compared the effects of a 12-week low-carbohydrate, high-fat diet with a conventional, high-carbohydrate, low-fat diet on weight reduction and metabolic health outcomes in at-risk New Zealand Defence Force personnel. In this randomised controlled trial, 41 overweight personnel were assigned to intervention and control groups. Weight, waist circumference, fasting lipids, and glycaemic control were assessed at baseline and at 12 weeks. Within-group change scores were analysed using the t statistic and interpreted using a p < 0.05 level of statistical significance. Between-group mean differences and confidence intervals were analysed using effect sizes and magnitude-based inferences. Twenty-six participants completed the trial (14 intervention, 12 control). Both groups showed statistically significant weight and waist circumference reductions; the intervention group significantly reduced triglycerides and serum glucose and significantly increased high-density lipoprotein cholesterol (HDLc). Relative to control, the intervention group showed small, possibly to likely beneficial effects for weight, triglycerides, glucose, insulin, and homeostasis model assessment of insulin resistance; moderate, likely beneficial effects for HDL cholesterol, triglyceride:HDLc ratio and HbA1c; and a small, likely harmful effect for low-density lipoprotein cholesterol. This dietary approach shows promise for short-term weight loss and improved metabolic health outcomes conditions compared with mainstream recommendations. It should be offered to defence force personnel at least as a viable alternative means to manage their weight and health.