Effect of a carbohydrate-restricted diet on weight loss in overweight and obese pediatric population: a meta-analysis of randomized controlled trials.

BACKGROUND: There are conflicting findings regarding the effect of low-carbohydrate diets on obesity-related factors. This study aimed to investigate the effect of a carbohydrate-restricted (CR) diet on changes in anthropometric indicators of adiposity and fat distribution in pediatrics populations. METHODS: A systematic search was conducted in PubMed/MEDLINE, Web of Science, Scopus, and Embase electronic databases using predefined keywords to identify all randomized controlled trials examining the effects of CR on obesity-related factors. The pooled weighted mean difference (WMD) and 95% confidence intervals (CI) were calculated using a random-effects model. RESULTS: Findings from 11 studies demonstrated significant reductions in weight (WMD: -2.31 kg; 95% CI: -4.44, -0.18), BMI (WMD:-1.08 kg/m2; 95% CI: -1.91, -0.26), and fat mass (WMD: -1.43%; 95% CI: -2.43 to -0.43) as well as a significant increase in adiponectin levels (WMD: 0.74 ng/ml; 95% CI: 0.02, 1.47) in the CR diet group compared to the control group. However, no significant effect was observed on BMI z-score (WMD:-0.10; 95% CI: -0.21, 0.01), waist circumference (WMD:-3.03 cm; 95% CI: -6.57, 0.51) or leptin levels (WMD: -0.82 ng/ml; 95% CI: -2.26, 0.61). Stratified analysis rrevealed a greater effect of CR on weight and BMI reduction in interventions ≤ 12 weeks and in very low-carbohydrate diets. CONCLUSIONS: In conclusion, it appears that CR diet, along with other lifestyle factors, can lead to significant improvements in weight loss on pediatrics with obesity/overweight.

Changes in the chronic and postprandial blood lipid profiles of trained competitive cyclists and triathletes following a ketogenic diet: a randomized crossover trial.

BACKGROUND: The ketogenic diet (KD) is the most popular carbohydrate restriction strategy for endurance athletes. However, because the primary goal of employing the KD is to gain a competitive advantage in competition, endurance athletes may be less concerned with the influence of the KD on their cardiometabolic health; particularly their blood lipid profiles. Thus, the purpose of this study was to examine the chronic and postprandial blood lipid alterations following a two-week ad libitum KD compared to an ad libitum high-carbohydrate diet (HCD) and the athletes' habitual diet (HD) in a group of trained competitive cyclists and triathletes. METHODS: Six trained competitive cyclists and triathletes (female: 4, male: 2; age: 37.2 ± 12.2) completed this randomized crossover trial, which required them to follow a two-week ad libitum KD and HCD in a randomized order after their HD. Fasting blood lipids were collected following their HD and after two-weeks of the KD and HCD conditions. Postprandial blood lipid responses to a test meal reflective of the assigned diet were collected at the end of each diet condition. RESULTS: Fasting total cholesterol (TC) was significantly higher following the KD compared to the HD (p < 0.001) and HCD (p = 0.006). Postprandial incremental area under the curve for triglycerides (TRG), TRG:HDL ratio, and VLDL-C were significantly higher following the KD test meal compared to the HD (all p < 0.001) and HCD (all p = 0.001) test meals but LDL-C and LDL:HDL ratio were significantly lower following the KD compared to the HD and HCD test meals (all p < 0.001). CONCLUSIONS: Trained competitive cyclists and triathletes demonstrate increased TC in response to a two-week KD compared to a HCD or HD. Endurance athletes contemplating a KD should consider the potential for these blood lipid alterations, and future research should focus on postprandial blood lipid responses to determine if these changes manifest in chronic blood lipid shifts. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04097171 (11 October 2019).

Defining "low-carb" in the scientific literature: A scoping review of clinical studies.

There remains a lack of scientific consensus on what level of carbohydrate intake constitutes low-carbohydrate diets. We conducted a scoping review to understand how low-carbohydrate diets were defined in the peer-reviewed literature. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement scoping review extension. Three electronic databases were searched for clinical studies in English. We identified 508 articles (317 randomized controlled, 99 cross-over, 33 before-and-after, 12 non-randomized, and 47 other clinical trials). Most examined effects of low-carbohydrate diets in healthy adults (62.4%), 40 to 59 years old (55.5%), with obesity or overweight (66.1%). The majority reported effects on weight or body composition (29.9%), diabetes (18.7%), or cardiovascular risk factors (12.9%) as primary outcomes. Most articles (56.9%) reported percent of energy from carbohydrates, and of those, 60.3% defined low-carbohydrate diets as being ≤30% of energy from carbohydrates. Some articles (22.9%) reported grams of carbohydrates per day, and of those, most defined low-carbohydrate diets as being under ∼100 grams of carbohydrates per day. Systematic reviews and dose-response meta-regressions utilizing patient-level data on carbohydrate intake, status markers (e.g., RQ/ketones), and health outcomes would be useful in informing consensus around a standardized definition.

Does a Ketogenic Diet Have a Place Within Diabetes Clinical Practice? Review of Current Evidence and Controversies.

Carbohydrate restriction has gained increasing popularity as an adjunctive nutritional therapy for diabetes management. However, controversy remains regarding the long-term suitability, safety, efficacy and potential superiority of a very low carbohydrate, ketogenic diet compared to current recommended nutritional approaches for diabetes management. Recommendations with respect to a ketogenic diet in clinical practice are often hindered by the lack of established definition, which prevents its capacity to be most appropriately prescribed as a therapeutic option for diabetes. Furthermore, with conflicted evidence, this has led to uncertainty amongst clinicians on how best to support and advise their patients. This review will explore whether a ketogenic diet has a place within clinical practice by reviewing current evidence and controversies.

Effectiveness of Technology-Enabled, Low Carbohydrate Dietary Interventions, in the Prevention or Treatment of Type 2 Diabetes Mellitus in Adults: A Systematic Literature Review of Randomised Controlled and Non-Randomised Trials.

Evidence suggests that low carbohydrate dietary (LCD) approaches can improve glycaemic control and may result in type 2 diabetes mellitus (T2DM) remission. This systematic literature review (SLR) aimed to assess the effectiveness of technology-enabled LCD interventions in the management of people with prediabetes or T2DM. Data sources included Medline, Embase, CINAHL, and Web of Science. Randomised (RCTs) or non-randomised (non-RCTs) controlled trials investigating the effect of technology-enabled LCDs (<130 g/day) or very low carbohydrate diets (VLCDs < 50 g/day) on glycosylated haemoglobin A1c (HbA1c) for at least three months and published in English between 2009 and 2023 were included. Risk of bias assessment, data extraction, and synthesis were conducted using standard tools and procedures. Six studies (two RCTs and four non-RCTs, total sample, n = 1519) were identified and included in the SLR. Two studies examining LCDs reported significant reductions in mean HbA1c (0.4% and -1.2%) and weight loss (-3.8 kg and -7.5 kg) at one year. Three studies examining VLCDs reported significant reductions in mean HbA1c (-0.8% to -1.3%) and weight loss (-12 kg to -14 kg) up to two years. Technology-enabled LCD or VLCD interventions can be a novel approach in helping people with prediabetes or T2DM self-manage their condition and possibly achieve remission. However, further research is required to determine the sustainability, effectiveness, and safety of this approach.

Impact of a Low-Carbohydrate Compared with Low-Fat Breakfast on Blood Glucose Control in Type 2 Diabetes: A Randomized Trial.

BACKGROUND: In type 2 diabetes (T2D), consuming carbohydrates results in a rapid and large increase in blood glucose, particularly in the morning when glucose intolerance is highest. OBJECTIVES: We investigated if a low-carbohydrate (LC) breakfast (∼465 kcal: 25 g protein, 8 g carbohydrates, and 37 g fat) could improve glucose control in people with T2D when compared with a low-fat control (CTL) breakfast (∼450 kcal:20 g protein, 56 g carbohydrates, and 15 g fat). METHODS: Participants with T2D (N = 121, 53% women, mean age 64 y) completed a remote 3-month parallel-group randomized controlled trial comparing a LC with standard low-fat guideline CTL breakfast. The change in HbA1c was the prespecified primary outcome. Continuous glucose monitoring, self-reported anthropometrics, and dietary information were collected for an intention-to-treat analysis. RESULTS: HbA1c was reduced (-0.3%; 95% CI: -0.4%, -0.1%) after 12 wks of a LC breakfast, but the between-group difference in HbA1c was of borderline statistical significance (-0.2; 95% CI: -0.4, 0.0; P = 0.06). Self-reported total daily energy (-242 kcal; 95% CI: -460, -24 kcal; P = 0.03) and carbohydrate (-73 g; 95% CI: -101, -44 g; P < 0.01) intake were lower in the LC group but the significance of this difference is unclear. Mean and maximum glucose, area under the curve, glycemic variability, standard deviation, and time above range were all significantly lower, and time in the range was significantly higher, in the LC group compared with CTL (all P < 0.05). CONCLUSIONS: Advice and guidance to consume a LC breakfast appears to be a simple dietary strategy to reduce overall energy and carbohydrate intake and improve several continuous glucose monitoring variables when compared with a CTL breakfast in persons living with T2D. The trial was registered at clinicaltrials.gov as NCT04550468.

Ketogenic diets composed of long-chain and medium-chain fatty acids induce cardiac fibrosis in mice.

PURPOSE: Heart diseases are the leading cause of death worldwide. Metabolic interventions via ketogenic diets (KDs) have been used for decades to treat epilepsy, and more recently, also diabetes and obesity, as common comorbidities of heart diseases. However, recent reports linked KDs, based on long-chain triglycerides (LCTs), to cardiac fibrosis and a reduction of heart function in rodents. As intervention using medium-chain triglycerides (MCTs) was recently shown to be beneficial in murine cardiac reperfusion injury, the question arises as to what extent the fatty acid (FA)-composition in a KD alters molecular markers of FA-oxidation (FAO) and modulates cardiac fibrotic outcome. METHODS: The effects of LCT-KD as well as an LCT/MCT mix (8:1 ketogenic ratio) on cardiac tissue integrity and the plasma metabolome were assessed in adult male C57/BL6NRJ mice after eight weeks on the respective diet. RESULTS: Both KDs resulted in increased amount of collagen fibers and cardiac tissue was immunologically indistinguishable between groups. MCT supplementation resulted in i) profound changes in plasma metabolome, ii) reduced hydroxymethylglutaryl-CoA synthase upregulation, and mitofusin 2 downregulation, iii) abrogation of LCT-induced mitochondrial enlargement, and iv) enhanced FAO profile. Contrary to literature, mitochondrial biogenesis was unaffected by KDs. We propose that the observed tissue remodeling is caused by the accumulation of 4-hydroxy-2-nonenal protein adducts, despite an inconspicuous nuclear factor (erythroid-derived 2)-like 2 pathway. CONCLUSION: We conclude that regardless of the generally favorable effects of MCTs, they cannot inhibit 4-hydroxy-2-nonenal adduct formation and fibrotic tissue formation in this setting. Furthermore, we support the burgeoning concern about the effect of KDs on the cardiac safety profile.

Diabesity and Dietary Interventions: Evaluating the Impact of Mediterranean Diet and Other Types of Diets on Obesity and Type 2 Diabetes Management.

BACKGROUND: Diabesity, the intersection of obesity and diabetes, presents a global health crisis with profound implications. Addressing diabesity requires multifaceted strategies, with diet playing a pivotal role. Over the last 15 years, clinical studies have intensified their exploration of various dietary approaches in diabesity management. This literature review aims to synthesize findings from clinical studies conducted in the last 15 years, shedding light on the efficacy, mechanisms, and nuances of different diet types in diabesity management with special focus on the Mediterranean diet (MD). METHODS: Thorough research of academic databases yielded a collection of relevant clinical studies. These studies encompassed a range of dietary strategies, including the MD, low-carbohydrate diets, plant-based diets, high-protein diets, low-fat regimens, and intermittent fasting. Key findings, methodologies, and outcomes were thoroughly extracted and analyzed. RESULTS: The last 15 years have witnessed considerable improvements in recognizing the role of human nutritional habits in diabesity management. The MD appears to be the most well-recognized diet, exerting favorable effects against both obesity and diabetes. Low-carbohydrate diets were found to enhance glycemic regulation and decrease insulin resistance. Plant-based diets demonstrated potential benefits in weight management and cardiometabolic health. High-protein, low-fat dietary models exhibited positive effects on satiety and body weight decline. Intermittent fasting regimens also exerted metabolic improvements and body weight decline. Personalization emerged as a crucial factor in dietary recommendations. CONCLUSIONS: Clinical studies from the last 15 years underscore the intricate relationship between diet types and diabesity management. The above results contribute to an increasing body of evidence, emphasizing the need for tailored dietary approaches and especially the MD. Healthcare providers can utilize this knowledge to offer personalized dietary recommendations for individuals with diabesity, potentially curbing the rise of these twin epidemics and improving the well-being of affected populations.

The Data Behind Popular Diets for Weight Loss.

Both scientific evidence and popular diet trends have sought to identify the ideal diet for weight loss with strategies focused on either restricting carbohydrates or fat. While there is a strong physiologic rationale for either carbohydrate restriction or fat restriction to achieve a calorie deficit needed for weight loss, evidence from randomized controlled trials suggest either type of diet is effective for weight loss. The level of adherence, rather than macronutrient content, is the driver of successful weight loss.

Effects of low-carbohydrate diets versus low-fat diets on metabolic risk factors in overweight and obese adults: A meta-analysis of randomized controlled trials.

Background and aims: Low-carbohydrate diets (LCD) and low-fat diets (LFD) have shown beneficial effects on the management of obesity. Epidemiological studies were conducted to compare the effects of the two diets. However, the results were not always consistent. This study aimed to conduct a meta-analysis to compare the long-term effects of LCD and LFD on metabolic risk factors and weight loss in overweight and obese adults. Methods: We performed a systematic literature search up to 30 March, 2022 in PubMed, EMBASE, and Cochrane Library. The meta-analysis compared the effects of LCD (carbohydrate intake ≤ 40%) with LFD (fat intake < 30%) on metabolic risk factors and weight loss for ≥6 months. Subgroup analyses were performed based on participant characteristics, dietary energy intake, and the proportions of carbohydrates. Results: 33 studies involving a total of 3,939 participants were included. Compared with participants on LFD, participants on LCD had a greater reduction in triglycerides (-0.14 mmol/L; 95% CI, -0.18 to -0.10 mmol/L), diastolic blood pressure (-0.87 mmHg; 95% CI, -1.41 to -0.32 mmHg), weight loss (-1.33 kg; 95% CI, -1.79 to -0.87 kg), and a greater increase in high-density lipoprotein cholesterol (0.07 mmol/L; 95% CI, 0.06 to 0.09 mmol/L) in 6-23 months. However, the decrease of total cholesterol (0.14 mmol/L; 95% CI, 0.07 to 0.20 mmol/L) and low-density lipoprotein cholesterol (0.10 mmol/L; 95% CI, 0.06 to 0.14 mmol/L) was more conducive to LFD in 6-23 months. There was no difference in benefits between the two diets after 24 months. Subgroup analyses showed no significant difference in the reduction of total cholesterol, low-density lipoprotein cholesterol, and blood pressure between the two diets in participants with diabetes, hypertension, or hyperlipidemia. Conclusion: The results suggest that LCD and LFD may have specific effects on metabolic risk factors and weight loss in overweight and obese adults over 6 months. At 24 months, the effects on weight loss and improvement of metabolic risk factors were at least the same. These indicated that we might choose different diets to manage the overweight and obese subjects. However, the long-term clinical efficacy and effects of various sources of carbohydrates or fat in the two diets need to be studied in the future.

Effectiveness of low-carbohydrate diets for long-term weight loss in obese individuals: A meta-analysis of randomized controlled trials.

AIM: To assess whether low-carbohydrate (LC) diets are associated with differences in weight loss and well-being in people with obesity, and their cardiovascular and renal safety. MATERIALS AND METHODS: A meta-analysis of randomized controlled trials longer than 3 months, retrieved through an extensive search on MedLine and Embase databases, comparing weight loss with LC and control diets in people with body mass index (BMI) greater than 30 kg/m2 , was conducted. RESULTS: We retrieved 25 trials. Compared with controls, LC diets were associated with significant reduction of body weight at 3-4 (MD -2.59 [-3.93, -1.25] kg) and 6-8 months (MD -2.64 [-4.32, -0.95]), but no difference at 10-14 and 18-30 months, and significantly greater BMI reduction at 3-4 months (-1.66 [-2.70, -0.61] kg/m2 ), but not at other time points. Because only four trials reported data on renal function and psychological variables, renal safety and impact on well-being could not be assessed. Differences in fasting plasma glucose at any time point were not statistically significant. No significant differences in total or LDL cholesterol or blood pressure were found in the long term, whereas a long-term reduction of triglycerides (23.26 [-45.53, -0.98] mg/dl at 18-30 months), and increase of HDL cholesterol (MD 4.94 [0.30, 9.57] mg/dl at 18-30 months), were observed. CONCLUSION: LC diets are associated with greater short-term weight loss than non-carbohydrate-restricted diets and a longer term favourable effect on cardiovascular risk factors. Further evidence on long-term efficacy and renal safety is needed before LC diets can be recommended as the preferred diets in obese people.

Low-Carbohydrate-Diet Score and Mortality in Adults With and Without Chronic Kidney Disease: Results From the Third National Health and Nutrition Examination Survey.

OBJECTIVE: The long-term safety of consuming low-carbohydrate diets (LCDs) remains controversial. As high protein and high fat might accelerate chronic kidney disease (CKD) progression, the impact of LCD on mortality might be different in subjects with CKD and subjects without CKD. Therefore, the objective of this study was to assess the association of LCD with mortality among individuals with and without CKD. METHODS: Data from 1158 subjects with CKD and 9523 subjects without CKD in the Third National Health and Nutrition Examination Survey were analyzed. The LCD score was calculated based on a 24-hour dietary recall interview. Mortality was from baseline until 31 December 2015. Cox proportional hazards regression models were fitted to estimate multivariable-adjusted hazard ratios and 95% confidence intervals. RESULTS: During the median follow-up of 24 years, 751 (65%) deaths and 2624 (28%) deaths were recorded in the CKD group and the non-CKD group, respectively. The multivariable-adjusted hazard ratio for all-cause mortality comparing the highest versus lowest quarters of LCD score was 1.51 (95% confidence interval, 1.01-2.25, P for trend = 0.045) in the CKD group. However, there were no association between the LCD score and all-cause mortality in the non-CKD group. CONCLUSIONS: The LCD scores were found significantly positively associated with all-cause mortality in adults with CKD, but not in adults without CKD.

Gut Microbiota Serves a Predictable Outcome of Short-Term Low-Carbohydrate Diet (LCD) Intervention for Patients with Obesity.

To date, much progress has been made in dietary therapy for obese patients. A low-carbohydrate diet (LCD) has reached a revival in its clinical use during the past decade with undefined mechanisms and debatable efficacy. The gut microbiota has been suggested to promote energy harvesting. Here, we propose that the gut microbiota contributes to the inconsistent outcome under an LCD. To test this hypothesis, patients with obesity or patients who were overweight were randomly assigned to a normal diet (ND) or an LCD group with ad libitum energy intake for 12 weeks. Using matched sampling, the microbiome profile at baseline and end stage was examined. The relative abundance of butyrate-producing bacteria, including Porphyromonadaceae Parabacteroides and Ruminococcaceae Oscillospira, was markedly increased after LCD intervention for 12 weeks. Moreover, within the LCD group, participants with a higher relative abundance of Bacteroidaceae Bacteroides at baseline exhibited a better response to LCD intervention and achieved greater weight loss outcomes. Nevertheless, the adoption of an artificial neural network (ANN)-based prediction model greatly surpasses a general linear model in predicting weight loss outcomes after LCD intervention. Therefore, the gut microbiota served as a positive outcome predictor and has the potential to predict weight loss outcomes after short-term LCD intervention. Gut microbiota may help to guide the clinical application of short-term LCD intervention to develop effective weight loss strategies. (This study has been registered at the China Clinical Trial Registry under approval no. ChiCTR1800015156). IMPORTANCE Obesity and its related complications pose a serious threat to human health. Short-term low-carbohydrate diet (LCD) intervention without calorie restriction has a significant weight loss effect for overweight/obese people. Furthermore, the relative abundance of Bacteroidaceae Bacteroides is a positive outcome predictor of individual weight loss after short-term LCD intervention. Moreover, leveraging on these distinct gut microbial structures at baseline, we have established a prediction model based on the artificial neural network (ANN) algorithm that could be used to estimate weight loss potential before each clinical trial (with Chinese patent number 2021104655623). This will help to guide the clinical application of short-term LCD intervention to improve weight loss strategies.

Low Carbohydrate Dietary Approaches for People With Type 2 Diabetes-A Narrative Review.

Although carbohydrate restriction is not a new approach for the management of Type 2 diabetes, interest in its safety and efficacy has increased significantly in recent years. The purpose of the current narrative review is to summarise the key relevant research and practical considerations in this area, as well as to explore some of the common concerns expressed in relation to the use of such approaches. There is a strong physiological rationale supporting the role of carbohydrate restriction for the management of Type 2 diabetes, and available evidence suggests that low carbohydrate dietary approaches (LCDs) are as effective as, or superior to, other dietary approaches for its management. Importantly, LCDs appear to be more effective than other dietary approaches for facilitating a reduction in the requirement for certain medications, which leads to their effects on other health markers being underestimated. LCDs have also been demonstrated to be an effective method for achieving remission of Type 2 diabetes for some people. The available evidence does not support concerns that LCDs increase the risk of cardiovascular disease, that such approaches increase the risk of nutrient deficiencies, or that they are more difficult to adhere to than other dietary approaches. A growing number of organisations support the use of LCDs as a suitable choice for individuals with Type 2 diabetes.

New obesity treatment: Fasting, exercise and low carb diet - The NOT-FED study.

INTRODUCTION: Due to high rates of obesity in Canada, weight loss is an important primary care challenge. Recent innovations in strategies include intermittent fasting and low-carbohydrate diets, with limited research in a rural setting. METHODS: This prospective 1-year observational study provided patients in Sioux Lookout, Northwestern Ontario with information on fasting and low-carbohydrate diets. Patients were recommended to attend every 3 months for measurements of weight, waist circumference, body mass index (BMI) and blood pressure. Initial and 6-month bloodwork included A1c and Lipids. A survey of health status and diet was administered at 6 months. RESULTS: Of the 94 initial registrants, 36 participants completed 1 year and achieved a 9% weight loss and an 8.6% decrease in BMI and waist circumference. Most participants were female with an average age of 60 years. Clinically insignificant changes in blood pressure and serology were observed. Participants reported few side effects and good compliance with intermittent fasting, averaging 15 h/day, 6 days/week. As in other dietary studies, the dropout rate was high at 62%. CONCLUSION: This low-resource initiative was successful in assisting self-selected patients at a rural primary care clinic to achieve significant weight loss at 1-year. This approach is practical and is fertile ground for ongoing research.

Introduction: En raison du taux élevé d'obésité au Canada, la perte pondérale est un énorme défi en première ligne. Les récentes innovations stratégiques incluent le jeûne intermittent et les régimes faibles en glucides, qui ont fait l'objet de peu de recherche dans les contextes ruraux. Méthodologie: Cette étude prospective d'observation d'un an a fourni aux patients de Sioux Lookout, du Nord-Ouest de l'Ontario de l'information sur le jeûne et les régimes faibles en glucides. On recommandait aux patients de se présenter tous les 3 mois pour mesurer le poids, le tour de taille, l'IMC et la tension artérielle. Les analyses sanguines initiales et à 6 mois comptaient les taux d'HbA1C et de lipides. Un sondage sur l'état de santé et le régime alimentaire était administré à 6 mois. Résultats: Sur les 94 personnes initialement inscrites, 36 participants ont terminé l'étude d'un an et ont perdu 9 % de leur poids et ont réduit l'IMC et le tour de taille de 8,6 %. La plupart des participants étaient de sexe féminin et l'âge moyen était de 60 ans. Des variations significatives sur le plan clinique de la tension artérielle et de la sérologie ont été observées. Les participants ont signalé peu d'effets indésirables et ont bien observé le jeûne intermittent, en moyenne pendant 15 heures/jour, 6 jours sur 7. Tout comme dans les autres études sur les régimes alimentaires, le taux d'abandons était élevé, à 62 %. Conclusion: Cette initiative nécessitant peu de ressources a réussi à aider les patients volontaires recrutés dans une clinique rurale de première ligne à perdre significativement de poids à un an. Cette approche est pratique et est un terreau fertile pour la recherche qui continue. Mots-clés: diabète, obésité, régimes faibles en glucides, jeûne intermittent.

Low-carbohydrate diet and maternal glucose metabolism in Chinese pregnant women.

Few studies have suggested that long-term adherence to low-carbohydrate diets (LCD) may affect maternal glucose metabolism in Western countries. We aimed to investigate the association between LCD during pregnancy and glucose metabolism in a Chinese population. A total of 1018 women in mid-pregnancy were recruited in 2017-2018. Participants underwent a 75 g oral glucose tolerance test (OGTT). Daily dietary intakes over the past month were accessed using a validated FFQ. The overall, animal and vegetable LCD scores which represent adherence to different low-carbohydrate dietary patterns were calculated. Mixed linear regression and generalised linear mixed regression were conducted to evaluate the associations between LCD scores and maternal glucose metabolism. Of the 1018 subjects, 194 (19·1 %) were diagnosed with gestational diabetes mellitus (GDM). The overall LCD score (ß: 0·024, se 0·008, PFDR = 0·02) and animal LCD score (ß: 0·023, se 0·008, PFDR = 0·02) were positively associated with OGTT 1-h glucose. No significant associations were found between the three different LCD scores with fasting plasma glucose, OGTT 2-h glucose, or insulin resistance, respectively. Compared with the lowest quartile, the crude OR of GDM for the highest quartile were 1·84 (95 % CI 1·14, 2·95) for overall LCD score (Pfor trend = 0·02) and 1·56 (95 % CI 1·00, 2·45) for animal LCD score (Pfor trend = 0·02). However, these associations became non-significant after adjustment for covariates. In conclusion, a low-carbohydrate dietary pattern with high animal protein and fat is associated with higher postprandial 1-h glucose levels in Chinese pregnant women.

JCL roundtable: Low-carbohydrate diets.

Low- and very-low-carbohydrate diets have long attracted popular interest in the US and variably throughout the world. The potential value of these diets was recognized recently in a Consensus Report from the American Diabetes Association and expanded in a Scientific Statement from the National Lipid Association. Scientific evidence remains incomplete, but is beginning to catch up with popular trends. In this JCL Roundtable, 3 experts discuss the evidence behind these diets, their current place in nutrition practice, and areas needing more study. The carbohydrate-insulin model of obesity is presented as one explanation for dietary effectiveness. Ongoing research will delineate this model further. The experts, all clinicians, give practical advice for when and how to incorporate low-carbohydrate principles into dietary counseling.

Low-carbohydrate diets and type 2 diabetes treatment: a meta-analysis of randomized controlled trials.

AIM: To assess whether LC diets are associated with long-term improvement in glycemic control and weight loss in people with T2DM, and their cardiovascular and renal safety. METHODS: Meta-analysis of randomized controlled trials lasting more than 3 months, retrieved through extensive search on PubMed, Embase, ClinicalTrial.gov, Cochrane databases up to March 1st, comparing LC diets and balanced carbohydrate diets in people with T2DM. RESULTS: We retrieved 37 trials, including 3301 patients. Average carbohydrate intake in LC diets was 36% of total energy. LC diets were associated with significant reduction of HbA1c at 3 months (MD - 0.17%, 95% CI - 0.27, - 0.07), no difference at 6 and 12 months, and significant increase at 24 months (MD 0.23%, 95% CI MD 0.02, 0.44). VLC diets were associated with significant HbA1c reduction at 3 and 6 months (MD - 0.43% - 0.60, - 0.26%, and MD - 0.40% 95% CI - 0.59, - 0.22, respectively), but not at 12 and 24 months. LC diets were associated with significant BMI reduction at 6 months (- 1.35 kg/m2 95% CI, - 2.18, - 0.52), but not at other time points. Only a minority of trials reported data on renal function, so renal safety could not be assessed. No significant differences in body weight, lipid profile, or blood pressure were found in the long term. CONCLUSION: LC diets may produce small short-term improvements in HbA1c and weight, which are not maintained in the long term. Data on their renal safety are insufficient.

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.