Effects of Intermittent Energy Restriction Combined with a Mediterranean Diet on Reducing Visceral Adiposity: A Randomized Active Comparator Pilot Study

Comparing caloric restriction regimens for effective weight management in adults: a systematic review and network meta-analysis

BACKGROUND

Randomized controlled trials have confirmed the effectiveness of four prevalent caloric restriction regimens in reducing obesity-related health risks. However, there is no consensus on the optimal regimen for weight management in adults.

METHODS

We systematically searched PubMed, Embase, Web of Science, and Cochrane CENTRAL up to January 15, 2024, for randomized controlled trials (RCT) involving adults, evaluating the weight-loss effects of alternate day fasting (ADF), short-term fasting (STF), time-restricted eating (TRE), and continuous energy restriction (CER). The primary outcome was body weight, with secondary outcomes including BMI, fat mass, lean mass, waist circumference, fasting glucose, HOMA-IR, and adverse events. Bayesian network meta-analysis was conducted, ranking regimens using the surface under the cumulative ranking curve and the probability of being the best. Study quality was assessed using the Confidence in Network Meta-Analysis tool.

RESULTS

Data from 47 RCTs (representing 3363 participants) were included. ADF showed the most significant body weight loss (Mean difference (MD): -3.42; 95% Confidence interval (CI): -4.28 to -2.55), followed by TRE (MD: -2.25; 95% CI: -2.92 to -1.59). STF (MD: -1.87; 95% CI: -3.32 to -0.56) and CER (MD: -1.59; 95% CI: -2.42 to -0.79) rank third and fourth, respectively. STF lead to decline in lean mass (MD: -1.26; 95% CI: -2.16, -0.47). TRE showed benefits on fasting glucose (MD: -2.98; 95% CI: -4.7, -1.26). Subgroup analysis revealed all four caloric restriction regimens likely lead to modest weight loss after 1-3 months, with ADF ranked highest, but by 4-6 months, varying degrees of weight regain occur, particularly with CER, while interventions lasting 7-12 months may result in effective weight loss, with TRE potentially ranking first during both the 4-6 months and 7-12 months periods. ADF showing fewer and shorter-lasting physical symptoms.

CONCLUSION

All four included regiments were effective in reducing body weight, with ADF likely having the most significant impact. Each regimen likely leads to modest weight loss after 1-3 months, followed by weight regain by 4-6 months. However, interventions lasting 7-12 months achieve greater weight loss overall.

TRIAL REGISTRATION

PROSPERO: CRD42022382478.

Visceral Fat-Reducing Effect of Novel Dietary Intervention Program: A Randomized Controlled Trial in Japanese Males

Background/Objectives: Reducing visceral fat is a critical factor in preventing obesity-related health complications. In this study, we evaluated the effectiveness of our previously reported novel dietary intervention program, "Optimized Nutri-Dense Meals", designed according to the Dietary Reference Intakes (DRIs) in Japan in reducing visceral fat. Method: This open-label, randomized controlled trial included 100 Japanese males with obesity or overweight. In total, 50 participants were assigned to a control group that continued their usual diets, and the other 50 consumed test meals twice per week for four weeks (test group). Result: The primary outcome, visceral fat area, significantly decreased in the test group compared to that in the control group (-7.5 cm2, confidence interval [CI]: -14.3 to -0.6). In addition, we measured the changes in gut flora and work productivity. The abundance of Bifidobacterium (+1.5%, CI: 0.3-2.7) and Christensenellaceae (+0.4%, CI: 0.01-0.8) increased significantly in the test group compared with those in the control group. Work Limitation Questionnaire Japanese version scores representing presenteeism also significantly increased in the test group (+1.2 points, CI: 0.2-2.3) compared with the control group. Conclusions: These findings suggest that dietary interventions based on Japanese DRIs can effectively decrease visceral fat and improve health outcomes over the short term without the need for a complete dietary overhaul.

Every-other-day fasting inhibits pyroptosis while regulating bile acid metabolism and activating TGR5 signaling in spinal cord injury

Every-other-day fasting (EODF) is a form of caloric restriction that alternates between periods of normal eating and fasting, aimed at preventing and treating diseases. This approach has gained widespread usage in basic research on neurological conditions, including spinal cord injury, and has demonstrated significant neuroprotective effects. Additionally, EODF is noted for its safety and feasibility, suggesting broad potential for application. This study aims to evaluate the therapeutic effects of EODF on spinal cord injury and to investigate and enhance its underlying mechanisms. Initially, the SCI rat model was utilized to evaluate the effects of EODF on pathological injury and motor function. Subsequently, considering the enhancement of metabolism through EODF, bile acid metabolism in SCI rats was analyzed using liquid chromatography-mass spectrometry (LC-MS), and the expression of the bile acid receptor TGR5 was further assessed. Ultimately, it was confirmed that EODF influences the activation of microglia and NLRP3 inflammasomes associated with the TGR5 signaling, along with the expression of downstream pyroptosis pathway related proteins and inflammatory cytokines, as evidenced by the activation of the NLRP3/Caspase-1/GSDMD pyroptosis pathway in SCI rats. The results demonstrated that EODF significantly enhanced the recovery of motor function and reduced pathological damage in SCI rats while controlling weight gain. Notably, EODF promoted the secretion of bile acid metabolites, activated TGR5, and inhibited the NLRP3/Caspase-1/GSDMD pyroptosis pathway and inflammation in these rats. In summary, EODF could mitigate secondary injury after SCI and foster functional recovery by improving metabolism, activating the TGR5 signaling and inhibiting the NLRP3 pyroptosis pathway.

Effect of Intermittent vs. Continuous Energy Restriction on Visceral Fat: Protocol for The Healthy Diet and Lifestyle Study 2 (HDLS2)

Obesity in the United States and Western countries represents a major health challenge associated with an increased risk of metabolic diseases, including cardiovascular disease, hypertension, diabetes, and certain cancers. Our past work revealed a more pronounced obesity-cancer link in certain ethnic groups, motivating us to develop a tailored dietary intervention called the Healthy Diet and Lifestyle 2 (HDLS2). The study protocol is described herein for this randomized six-month trial examining the effects of intermittent energy restriction (5:2 Diet) plus the Mediterranean dietary pattern (IER + MED) on visceral adipose tissue (VAT), liver fat, and metabolic biomarkers, compared to a standard MED with daily energy restriction (DER + MED), in a diverse participant group. Using MRI and DXA scans for body composition analysis, as well as metabolic profiling, this research aims to contribute to nutritional guidelines and strategies for visceral obesity reduction. The potential benefits of IER + MED, particularly regarding VAT reduction and metabolic health improvement, could be pivotal in mitigating the obesity epidemic and its metabolic sequelae. The ongoing study will provide essential insights into the efficacy of these energy restriction approaches across varied racial/ethnic backgrounds, addressing an urgent need in nutrition and metabolic health research. Registered Trial, National Institutes of Health, ClinicalTrials.gov (NCT05132686).

The effect of intermittent fasting on microbiota as a therapeutic approach in obesity

Obesity, a public health challenge, arises from a complex interplay of factors such as dietary habits and genetic predisposition. Alterations in gut microbiota, characterized by an imbalance between Firmicutes and Bacteroidetes, further exacerbate metabolic dysregulation, promoting inflammation and metabolic disturbances. Intermittent fasting (IF) emerges as a promising dietary strategy showing efficacy in weight management and favoring fat utilization. Studies have used mice as animal models to demonstrate the impact of IF on gut microbiota composition, highlighting enhanced metabolism and reduced inflammation. In humans, preliminary evidence suggests that IF promotes a healthy microbiota profile, with increased richness and abundance of beneficial bacterial strains like Lactobacillus and Akkermansia. However, further clinical trials are necessary to validate these findings and elucidate the long-term effects of IF on microbiota and obesity. Future research should focus on specific tissues and cells, the use of advanced -omics techniques, and exploring the interaction of IF with other dietary patterns, to analyze microbiota composition, gene expression, and potential synergistic effects for enhanced metabolic health. While preliminary evidence supports the potential benefits of IF in obesity management and microbiota regulation, further research with diverse populations and robust methodologies is necessary to understand its implications and optimize personalized dietary interventions. This review explores the potential impact of IF on gut microbiota and its intricate relationship with obesity. Specifically, we will focus on elucidating the underlying mechanisms through which IF affects microbiota composition, as well as its subsequent effects on obesity.

Comparative efficacy of energy-restricted dietary interventions in overweight and obese populations: A systematic review and network meta-analysis

This meta-analysis compared the effectiveness of different energy-restricted diets on body composition, glucose metabolism, and lipid metabolism in overweight and obese populations. Five databases were searched to identify relevant studies in English from inception until July 20, 2023, for randomized controlled trials of at least 2 weeks duration assessing the effects of continuous energy-restricted diets compared with any intermittent energy-restricted diet in obesity adults. The risk of bias was assessed using the Cochrane Risk of Bias Tool version 2.0, while the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system was used to assess the certainty of the evidence. A non-informative prior distribution Bayesian network meta-analysis was conducted. Thirty-eight studies (3039 participants) assessing four energy-restricted diets were included. Three RCTs were at high risk of bias with a very low to moderate certainty of evidence. Combined with pairwise comparisons and surface under the cumulative ranking curve, alternate-day fasting may be the best energy restriction regimen with the potential to have the most beneficial effects on various aspects of the obesity population. More rigorously designed and long-term follow-up studies are warranted.

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.

An alternative approach to obesity treatment: intermittent fasting

Overweight and obesity are an important public health problem that affects a significant part of the world population and increases the risk of many metabolic diseases. Weight loss is the primary goal in obesity treatment, and many different dietary interventions are tried for this purpose. Intermittent fasting is a diet that has become popular in recent years with the weight loss it provides and includes periods of fasting and feeding. In addition to providing weight loss, intermittent fasting also has positive effects on important risk factors such as glucoregulatory parameters, blood lipids, and oxidative stress. Intermittent fasting appears to be an effective and safe way to achieve weight loss in obesity. It could also have therapeutic effects on obesity-related diseases. The aim of this review was to bring together up-to-date information on the effects of intermittent fasting on obesity and various obesity-related diseases, mechanisms of action, possible benefits and harms, and potential uses.

Dietary Patterns and the Prevalence of Noncommunicable Diseases in the PURE Poland Study Participants

The aim of the study was to analyze the association between dietary patterns (DP) identified in the group of Lower Silesia (Poland) inhabitants and the prevalence of selected noncommunicable diseases, such as total cardiovascular diseases (CVD), hypertension, diabetes, impaired fasting glucose (IFG), visceral obesity, and excessive body weight. This study involved 2023 subjects aged 35-70 years, from Wroclaw and surrounding villages. The assessment of food intake in the study group was assessed using the standardized Food Frequency Questionnaire. Dietary patterns were identified using the principal components analysis (PCA) with varimax rotation. Three dietary patterns were identified in the study group: unhealthy, healthy, and traditional. The prevalence of hypertension, diabetes, IFG, and visceral obesity decreased across the quartiles of healthy DP. Prevalence of IFG increased across the quartiles of unhealthy DP, but the prevalence of hypertension decreased. When the diet was more adherent to the traditional DP the prevalence of CVD, diabetes, IFG, visceral obesity, obesity, and being overweight was higher. DP abundant in fruits, vegetables, seeds, nuts, raisins, and unrefined grains, named "healthy dietary pattern", had a beneficial association with lower prevalence of selected noncommunicable diseases. DP abundant in meat products, but poor in fruits and vegetables were positively associated with higher prevalence of total CVD, diabetes, IFG, excessive body weight, and visceral obesity.

Mycobiome and Inflammatory Bowel Disease: Role in Disease Pathogenesis, Current Approaches and Novel Nutritional-based Therapies

Inflammatory bowel disease (IBD), a disorder characterized by chronic inflammation of the gastrointestinal (GI) tract and a range of adverse health effects including diarrhea, abdominal pain, vomiting, and bloody stools, affects nearly 3.1 million genetically susceptible adults in the United States today. Although the etiology of IBD remains unclear, genetics, stress, diet, and gut microbiota dysbiosis- especially in immunocompromised individuals- have been identified as possible causes of disease. Although previous research has largely focused on the role of bacteria in IBD pathogenesis, recently observed alterations of fungal load and biodiversity in the GI tract of afflicted individuals suggest interkingdom interactions amongst different gut microbial communities, particularly between bacteria and fungi. These discoveries point to the potential utilization of treatment approaches such as antibiotics, antifungals, probiotics, and postbiotics that target both bacteria and fungi in managing IBD. In this review, we discuss the impact of specific fungi on disease pathogenesis, with a focus on the highly virulent genus Candida and how the presence of certain co-enzymes impacts its virulence. In addition, we evaluate current gut microbiome-based therapeutic approaches with the intention of better understanding the mechanisms behind novel therapies.

Effects of a Dulaglutide plus Calorie-Restricted Diet versus a Calorie-Restricted Diet on Visceral Fat and Metabolic Profiles in Women with Polycystic Ovary Syndrome: A Randomized Controlled Trial

The effects of dulaglutide and a calorie-restricted diet (CRD) on visceral adipose tissue (VAT) and metabolic profiles in polycystic ovary syndrome (PCOS) have not been extensively investigated. In this study, we investigated whether dulaglutide combined with CRD could further reduce VAT and promote clinical benefits as compared with a CRD regimen alone in overweight or obese PCOS-affected women. Between May 2021 and May 2022, this single-center, randomized, controlled, open-label clinical trial was conducted. Overall, 243 participants with PCOS were screened, of which 68 overweight or obese individuals were randomly randomized to undergo dulaglutide combined with CRD treatment (n = 35) or CRD treatment alone (n = 33). The duration of intervention was set as the time taken to achieve a 7% weight loss goal from baseline body weight, which was restricted to 6 months. The primary endpoint was the difference in the change in VAT area reduction between the groups. The secondary endpoints contained changes in menstrual frequency, metabolic profiles, hormonal parameters, liver fat, and body composition. As compared with the CRD group, the dulaglutide + CRD group had a considerably shorter median time to achieve 7% weight loss. There was no significant between-group difference in area change of VAT reduction (-0.97 cm², 95% confidence interval from -14.36 to 12.42, p = 0.884). As compared with CRD alone, dulaglutide + CRD had significant advantages in reducing glycated hemoglobin A1c and postprandial plasma glucose levels. The results of the analyses showed different changes in menstruation frequency, additional metabolic profiles, hormonal markers, liver fat, and body composition between the two groups did not differ significantly. Nausea, vomiting, constipation, and loss of appetite were the main adverse events of dulaglutide. These results emphasize the value of dietary intervention as the first line of treatment for PCOS-affected women, while glucagon-like peptide 1 receptor agonist therapy provides an efficient and typically well tolerated adjuvant therapy to aid in reaching weight targets based on dietary therapy in the population of overweight/obese PCOS-affected women.

A Systematic Review of Literature on the Representation of Racial and Ethnic Minority Groups in Clinical Nutrition Interventions

The racial and ethnic disparities in diet-related chronic diseases are major concerns. This systematic review examines the extent to which diet-induced changes in health outcomes, such as cardiometabolic, inflammation, cancer, bone health, and kidney function outcomes, etc., have been reported and discussed by race or ethnicity in randomized trials with 2 or more diet arms that recruited both minority and non-Hispanic White groups. Databases (i.e., PubMed, Cochrane Library, and Web of Science) were searched up to August 2021. Thirty-four studies that discussed effects of defined dietary interventions on health outcomes by racial or ethnic minority group compared with non-Hispanic Whites were included in the systematic review (PROSPERO registration number: CRD42021229256). Acute trials and those with 1 diet arm that accounted for race or ethnicity in their analyses and studies that focused on a single racial or ethnic group were discussed separately. Most studies were conducted in Black compared with White adults testing effects of energy restriction, macronutrient modification, sodium reduction, or variations of the Dietary Approaches to Stop Hypertension (DASH) diet on cardiometabolic outcomes. There was limited focus on other minority groups. Evidence suggests greater blood pressure reduction for Black adults compared with Whites particularly with DASH (or similar) diets. Overall, there was limited consideration for group-specific eating patterns and diet acceptability. Overall risk of bias was low. With emerging precision nutrition initiatives that aim to optimize metabolic responses in population subgroups through tailored approaches, it is imperative to ensure adequate representation of racial and ethnic subgroups for addressing health disparities. Factors that help explain variability in responses such as socioecological context should be included and adequately powered. Given the racial and ethnic disparities in chronic diseases, studying the adoption, maintenance, and effectiveness of dietary interventions on health outcomes among different groups is critical for developing approaches that can mitigate diet-related health disparities.

Effect of Carbohydrate-Restricted Diets and Intermittent Fasting on Obesity, Type 2 Diabetes Mellitus, and Hypertension Management: Consensus Statement of the Korean Society for the Study of Obesity, Korean Diabetes Association, and Korean Society of Hypertension

Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations. A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled trials (RCTs) of carbohydrate-restricted diets and 10 articles on eight RCTs of IF was performed. Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes mellitus, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension. Here, we describe the results of our analysis and the evidence for these recommendations.

Effect of carbohydrate-restricted diets and intermittent fasting on obesity, type 2 diabetes mellitus, and hypertension management: consensus statement of the Korean Society for the Study of obesity, Korean Diabetes Association, and Korean Society of Hypertension

BACKGROUND

Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations.

METHODS

A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled clinical trials (RCTs) of carbohydrate-restricted diets and ten articles on eight RCTs of IF was performed.

RESULTS

Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension.

CONCLUSION

Here, we describe the results of our analysis and the evidence for these recommendations.

Comparison of the Effects of Intermittent Energy Restriction and Continuous Energy Restriction among Adults with Overweight or Obesity: An Overview of Systematic Reviews and Meta-Analyses

There is considerable heterogeneity across the evidence regarding the effects of intermittent energy restriction and continuous energy restriction among adults with overweight or obesity which presents difficulties for healthcare decision-makers and individuals. This overview of systematic reviews aimed to evaluate and synthesize the existing evidence regarding the comparison of the two interventions. We conducted a search strategy in eight databases from the databases’ inception to December 2021. The quality of 12 systematic reviews was assessed with A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) and the Grading of Recommendations Assessment, Development and Evaluation (GRADE). One review was rated as high quality, 1 as moderate, 4 as low, and 6 as critically low. A meta-analysis of the original studies was conducted for comparison of primary intermittent energy restriction protocols with continuous energy restriction. Intermittent energy restriction did not seem to be more effective in weight loss compared with continuous energy restriction. The advantages of intermittent energy restriction in reducing BMI and waist circumference and improvement of body composition were not determined due to insufficient evidence. The evidence quality of systematic reviews and original trials remains to be improved in future studies.

Effects of Intermittent Fasting in Human Compared to a Non-intervention Diet and Caloric Restriction: A Meta-Analysis of Randomized Controlled Trials

Background

The popularity of applying intermittent fasting (IF) has increased as more and more people are trying to avoid or alleviate obesity and metabolic disease. This study aimed to systematically explore the effects of various IF in humans.

Methods

The randomized controlled trials (RCTs) related to IF vs. non-intervention diet or caloric restriction (CR) were retrieved in PubMed, Web of Science, Cochrane Library database, and Embase. Extraction outcomes included, but were not limited to, weight, body mass index (BMI), waist circumference (WC), fasting glucose, and triglyceride (TG).

Results

This study includes 43 RCTs with 2,483 participants. The intervention time was at least 1 month, and the median intervention time was 3 months. Contrasting results between IF and non-intervention diet showed that participants had lower weight (weighted mean difference (WMD) = 1.10, 95% CI: 0.09–2.12, p = 0.03) and BMI after IF (WMD = 0.38, 95% CI: 0.08–0.68, p = 0.01). The WC of participants after IF decreased significantly compared with the non-intervention diet (WMD = 1.02, 95% CI: 0.06–1.99, p = 0.04). IF regulated fat mass (FM) more effectively than non-intervention diet (WMD = 0.74, 95% CI: 0.17–1.31, p = 0.01). The fat-free mass of people after IF was higher (WMD = −0.73, 95% CI: (−1.45)–(−0.02), p = 0.05). There was no difference in fasting blood glucose concentrations between participants in the after IF and non-intervention diet groups. The results of insulin concentrations and HOMA-IR, though, indicated that IF was significantly more beneficial than non-intervention diet (standard mean difference (SMD) = −0.21, 95% CI: 0.02–0.40, p = 0.03, and WMD = 0.35, 95% CI: 0.04–0.65, p = 0.03, respectively). Cholesterol and TG concentrations in participants after IF were also lower than that after a nonintervention diet (SMD = 0.22, 95% CI: 0.09–0.35, p = 0.001 and SMD = 0.13, 95% CI: 0.00–0.26, p = 0.05, respectively). IF outcomes did not differ from CR except for reduced WC.

Conclusion

Intermittent fasting was more beneficial in reducing body weight, WC, and FM without affecting lean mass compared to the non-intervention diet. IF also effectively improved insulin resistance and blood lipid conditions compared with non-intervention diets. However, IF showed less benefit over CR.

Effect of Carbohydrate-Restricted Diets and Intermittent Fasting on Obesity, Type 2 Diabetes Mellitus, and Hypertension Management: Consensus Statement of the Korean Society for the Study of Obesity, Korean Diabetes Association, and Korean Society of Hypertension

Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations. A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled trials (RCTs) of carbohydrate-restricted diets and 10 articles on eight RCTs of IF was performed. Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes mellitus, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension. Here, we describe the results of our analysis and the evidence for these recommendations.

The Association Between Regular Physical Exercise, Sleep Patterns, Fasting, and Autophagy for Healthy Longevity and Well-Being: A Narrative Review

This narrative review of the literature assessed whether regular physical exercise and sleep patterns, fasting and autophagy, altogether can be an adequate strategy for achieving healthy longevity and well-being within different stage of life. There are a large number of studies dealing with well-being and healthy longevity; however, few of them have given us a specific formula for how to live long and healthy. Despite all the advances that have been made to create adequate physical exercise programs, sleep patterns or nutritional protocols, the relation between different types of fasting, nutritional supplementation as well as regular physical exercise and sleep patterns have not yet been satisfactorily resolved to cause the best effects of autophagy and, therefore, well-being and healthy longevity. In this way, future studies should clarify more efficiently the relationship between these variables to understand the association between regular physical exercise, sleep patterns, fasting and autophagy for healthy longevity and well-being.

Effect of Epidemic Intermittent Fasting on Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Intermittent fasting (IF) has gained attention as a promising diet for weight loss and dysmetabolic diseases management. This systematic review aimed to investigate the effects of IF on cardiometabolic risk factors (CMRFs). A systematic literature search was carried out using three electronic databases, namely PubMed, Embase, and the Cochrane Library, until October 2020. Randomized controlled trials that compared the IF intervention with a control group diet were included. Fourteen effect sizes were expressed as weighted mean difference (WMD) using a fixed-effects model and 95% confidence intervals (CI). Compared to the ones within control groups, participants exposed to the IF intervention reduced their body weight (WMD, −1.78 kg; 95% CI, −2.21 to −1.35; p <0.05), waist circumference (WMD, −1.19 cm; 95% CI, −1.8 to −0.57; p <0.05), fat mass (WMD, −1.26 kg; 95% CI, −1.57 to −0.95; p <0.05), body mass index (WMD, −0.58 kg/m²; 95% CI, −0.8 to −0.37; p <0.05), systolic blood pressure (WMD, −2.14 mmHg; 95% CI: −3.54 to −0.73; p <0.05), diastolic blood pressure (WMD: −1.38 mmHg, 95% CI, −2.35 to −0.41, p <0.05), fasting blood glucose (WMD: −0.053 mmol/L; 95% CI: −0.105 to 0.001; p <0.05), fasting insulin (WMD, −0.8 mIU/L; 95% CI, −1.15 to −0.44; p <0.05), insulin resistance (WMD, −0.21; 95% CI, −0.36 to −0.05; p <0.05), total cholesterol (WMD, −0.10 mmol/L; 95% CI, −0.17 to −0.02; p <0.05), and triglycerides (WMD, −0.09 mmol/L; 95% CI, −0.13 to −0.04; p <0.05). No effects were observed for low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or glycosylated hemoglobin. This meta-analysis supports the role of IF in improving the component composition of CMRFs, including weight, waist circumference, fat mass, BMI, blood pressure, total cholesterol, triglycerides, fasting insulin, and insulin resistance, compared to a control group diet. Further research on IF interventions should take into account long-term and well-designed administration to draw definitive conclusions.

Which Diets Are Effective in Reducing Cardiovascular and Cancer Risk in Women with Obesity? An Integrative Review

Women are more affected by obesity than men which increases their risk of cancer and cardiovascular disease (CVD). Therefore, it is important to understand the effectiveness of different types of diet in the context of women's health. This review aims to summarize the scientific evidence on the effects of different types of diet for women with obesity and their impact on CVD and cancer risk. This review included epidemiological and clinical studies on adult women and different types of diets, such as the Mediterranean (MED) diet, the Traditional Brazilian Diet, the Dietary Approach to Stop Hypertension (DASH), intermittent fasting (IF), calorie (energy) restriction, food re-education, low-carbohydrate diet (LCD) and a very low-carbohydrate diet (VLCD). Our main findings showed that although LCDs, VLCD and IF are difficult to adhere to over an extended period, they can be good options for achieving improvements in body weight and cardiometabolic parameters. MED, DASH and the Traditional Brazilian Diet are based on natural foods and reduced processed foods. These diets have been associated with better women's health outcomes, including lower risk of CVD and cancer and the prevention and treatment of obesity.

Intermittent fasting versus continuous energy-restricted diet for patients with type 2 diabetes mellitus and metabolic syndrome for glycemic control: A systematic review and meta-analysis of randomized controlled trials

AIMS

To compare the safety of intermittent fasting (IF) with that of continuous energy-restricted diets (CERD) in patients with T2DM and metabolic syndrome who were overweight or obese and assess their effects on glycemic control and weight loss.

MATERIALS AND METHODS

We searched MEDLINE (Ovid), Embase, and SINOMED databases up to September 13, 2020. The major outcome was glycemic control and secondary outcomes were change in weight, fasting insulin, and lipid profile.

RESULTS

Of 84 retrieved studies, 5 met our inclusion criteria. Of these, four studies comprising 355 participants were included in the meta-analysis. Based on changes in HbA1c (-0.06, 95% confidence interval [CI] -0.27 to 0.16) and fasting plasma glucose (-0.27, 95% CI -0.76 to 0.22), IF and CERD had similar effects on glycemic control. Moreover, IF had a better effect on weight loss (-1.70, 95% CI -3.28 to -0.11 kg). Patients in both groups experienced similar improvements in fasting insulin and lipid profile as well as similar hypoglycemic events.

CONCLUSIONS

IF is a safe diet pattern and could be implemented for patients with T2DM or metabolic syndrome. Further studies with a larger sample size are needed to verify the effectiveness and safety of IF in patients with T2DM.

Assessing the Physiological Effects of Traditional Regional Diets Targeting the Prevention of Cardiovascular Disease: A Systematic Review of Randomized Controlled Trials Implementing Mediterranean, New Nordic, Japanese, Atlantic, Persian and Mexican Dietary Interventions

Traditional regional diets are considered as sustainable dietary patterns, while many have been examined with regard to their health benefits. The aim of the present systematic review was to aggerate all evidence on the physiological effects of regional diets among adults at high risk for cardiovascular disease (CVD). Three databases were searched for randomized controlled trials (RCTs) implementing any regional diet (Mediterranean (MedD), Persian, Southern European Atlantic, Japanese, Chinese, new Nordic, or other) while examining cardiovascular risk factors among adults at increased risk. Primary outcomes included anthropometric indices and secondary outcomes involved blood lipid concentrations, glucose metabolism, inflammation and other markers of CVD progression. Twenty RCTs fulfilled the study's criteria and were included in the qualitative synthesis, with the majority implementing a MedD. Adherence to most of the regional diets induced a reduction in the BW and anthropometric indices of the participants. The majority of RCTs with blood pressure endpoints failed to note a significant reduction in the intervention compared to the comparator arm, with the exception of some new Nordic and MedD ones. Despite the interventions, inflammation markers remained unchanged except for CRP, which was reduced in the intervention groups of one new Nordic, the older Japanese, and the Atlantic diet RCTs. With regard to blood lipids, regional diet interventions either failed to induce significant differences or improved selective blood lipid markers of the participants adhering to the experimental regional diet arms. Finally, in the majority of RCTs glucose metabolism failed to improve. The body of evidence examining the effect of regional dietary patterns on CVD risk among high-risk populations, while employing an RCT design, appears to be limited, with the exception of the MedD. More research is required to advocate for the efficacy of most regional diets with regard to CVD.

Management of Obesity in Cardiovascular Practice: JACC Focus Seminar

Obesity contributes to reduced life expectancy because of its link with type 2 diabetes and cardiovascular disease. Yet, targeting this poorly diagnosed, ill-defined, and underaddressed modifiable risk factor remains a challenge. In this review, we emphasize that the tendency among health care professionals to amalgam all forms of obesity altogether as a single entity may contribute to such difficulties and discrepancies. Obesity is a heterogeneous condition both in terms of causes and health consequences. Attention should be given to 2 prevalent subgroups of individuals: 1) patients who are overweight or moderately obese with excess visceral adipose tissue; and 2) patients with severe obesity, the latter group having distinct additional health issues related to their large body fat mass. The challenge of tackling high-cardiovascular-risk forms of obesity through a combination of personalized clinical approaches and population-based solutions is compounded by the current obesogenic environment and economy.

Hypotensive peptides derived from plant proteins

Hypertension is a risk factor for arteriosclerosis development and is recognized as a silent killer. Certain processed food materials, digested by protease or through the use of fermentation, have shown exertion of hypotensive effects in human clinical or animal studies, and hypotensive peptides were isolated from them. This review discusses the hypotensive peptides derived from plant proteins, such as grain, soy, vegetables, and seaweeds, and their hypotensive mechanisms. Although angiotensin I-converting enzyme (ACE) inhibition is often noted as one of the mechanisms that may exert antihypertensive effects, ACE inhibitory activity measured by in vitro studies is not associated with the actual hypotensive effect. Thus, this review only highlights the peptide hypotensive effect determined by in vivo studies. This review also discusses the tendency of the amino acid sequence of ACE-inhibitory hypotensive peptides and the possible additional effects of hypotensive peptides independent of ACE inhibition.

Beyond calorie restriction: aging as a biological target for nutrient therapies

Arguably, the most important discovery in the biology of aging to date was that simply reducing food intake extended life and improved many aspects of health in a diversity of animal species. The conventional wisdom that emerged from first 50 years of rodent food restriction studies included (1) that the longevity impact of restriction was greater the longer restriction was imposed, and (2) that restricting calories rather than any specific macronutrient was critical to its health and longevity benefits. However these assumptions began to crumble as more and more restriction research was performed on other species besides laboratory rodents. Recent investigations of flies, rodents, monkeys, and increasingly humans, has begun to parse how calorie restriction, protein restriction, intermittent fasting, and the temporal pattern of eating all impact the health benefits of food restriction. Fly research continues to inform, as it has repeatedly shown that genotype, age, sex, duration, and tempo restriction all affect the health impact. Ultimately, optimizing human diets will require a personalized approach using omics approaches.

The Long-Term Dietitian and Psychological Support of Obese Patients Who Have Reduced Their Weight Allows Them to Maintain the Effects

The role of post-therapeutic support after weight loss in obesity treatment is not fully understood. Therefore, weight maintenance after a successful weight loss intervention is not very common, especially in obese individuals. This randomized controlled study was conducted to explore the efficacy of following dietary and psychological support in a group of 36 obese individuals. Participants (22 women, 14 men aged 35.58 ± 9.85 years, BMI 35.04 ± 3.80 kg/m²) who completed a 12-month weight loss phase (balanced energy-restricted diet) were randomly allocated to receive 18-month support (SG) or no additional care (CG). The support phase included some elements of Ten Top Tips (TTT), cognitive behavioral therapy (CBT), motivational interviewing (MI) in combination with nutritional education and assessment of the level of physical activity. The primary outcome was the maintenance of anthropometric parameters at an 18-month follow-up. The secondary outcomes included evaluation of biochemical parameters and single nucleotide polymorphisms (SNPs) in genes connected with obesity. A comparison of SG vs. CG after a 30-month period of the study revealed significant differences in weight changes (−3.83 ± 6.09 vs. 2.48 ± 6.24 kg), Body Mass Index (−1.27 ± 2.02 vs. 0.72 ± 2.12 kg/m²), visceral adipose tissue (−0.58 ± 0.63 vs. 0.45 ± 0.74 L), and waist circumference (−4.83 ± 4.05 vs. 1.83 ± 5.97 cm). Analysis of SNPs (rs9939609 FTO, rs987237 TFAP2B, and rs894160 PLIN1) provided further insight into the potential modulating effect of certain genotypes on weight loss and maintenance and extended the knowledge of the potential benefits of personalized medicine. Post-therapeutical support in current clinical practice may increase the chances of long-term weight loss maintenance in obesity treatment even in patients with a genetic predisposition to excessive weight.

Adherence and Dietary Composition during Intermittent vs. Continuous Calorie Restriction: Follow-Up Data from a Randomized Controlled Trial in Adults with Overweight or Obesity

Although intermittent calorie restriction (ICR) has become popular as an alternative weight loss strategy to continuous calorie restriction (CCR), there is insufficient evidence on diet quality during ICR and on its feasibility over longer time periods. Thus, we compared dietary composition and adherence between ICR and CCR in a follow-up analysis of a randomized trial. A total of 98 participants with overweight or obesity [BMI (kg/m²) 25-39.9, 35-65 years, 49% females] were randomly assigned to ICR, operationalized as a "5:2 diet" (energy intake: ~100% on five non-restricted (NR) days, ~25% on two restricted (R) days), or CCR (daily energy intake: ~80%). The trial included a 12-week (wk) intervention phase, and follow-up assessments at wk24, wk50 and wk102. Apart from a higher proportion of energy intake from protein with ICR vs. CCR during the intervention (wk2: p < 0.001; wk12: p = 0.002), there were no significant differences with respect to changes in dietary composition over time between the groups, while overall adherence to the interventions appeared to be good. No significant difference between ICR and CCR regarding weight change at wk102 was observed (p = 0.63). However, self-reported adherence was worse for ICR than CCR, with 71.1% vs. 32.5% of the participants reporting not to or only rarely have followed the regimen to which they were assigned between wk50 and wk102. These results indicate that within a weight management setting, ICR and CCR were equivalent in achieving modest weight loss over two years while affecting dietary composition in a comparable manner.

Utility of self-rated adherence for monitoring dietary and physical activity compliance and assessment of participant feedback of the Healthy Diet and Lifestyle Study pilot

Background

We examined the utility of self-rated adherence to dietary and physical activity (PA) prescriptions as a method to monitor intervention compliance and facilitate goal setting during the Healthy Diet and Lifestyle Study (HDLS). In addition, we assessed participants’ feedback of HDLS. HDLS is a randomized pilot intervention that compared the effect of intermittent energy restriction combined with a Mediterranean diet (IER + MED) to a Dietary Approaches to Stop Hypertension (DASH) diet, with matching PA regimens, for reducing visceral adipose tissue area (VAT).

Methods

Analyses included the 59 (98%) participants who completed at least 1 week of HDLS. Dietary and PA adherence scores were collected 8 times across 12 weeks, using a 0–10 scale (0 = not at all, 4 = somewhat, and 10 = following the plan very well). Adherence scores for each participant were averaged and assigned to high and low adherence categories using the group median (7.3 for diet, 7.1 for PA). Mean changes in VAT and weight from baseline to 12 weeks are reported by adherence level, overall and by randomization arm. Participants’ feedback at completion and 6 months post-intervention were examined.

Results

Mean ± SE, dietary adherence was 6.0 ± 0.2 and 8.2 ± 0.1, for the low and high adherence groups, respectively. For PA adherence, mean scores were 5.9 ± 0.2 and 8.5 ± 0.2, respectively. Compared to participants with low dietary adherence, those with high adherence lost significantly more VAT (22.9 ± 3.7 cm² vs. 11.7 ± 3.9 cm² [95% CI, − 22.1 to − 0.3]) and weight at week 12 (5.4 ± 0.8 kg vs. 3.5 ± 0.6 kg [95% CI, − 3.8 to − 0.0]). For PA, compared to participants with low adherence, those with high adherence lost significantly more VAT (22.3 ± 3.7 cm² vs. 11.6 ± 3.6 cm² [95% CI, − 20.7 to − 0.8]). Participants’ qualitative feedback of HDLS was positive and the most common response, on how to improve the study, was to provide cooking classes.

Conclusions

Results support the use of self-rated adherence as an effective method to monitor dietary and PA compliance and facilitate participant goal setting. Study strategies were found to be effective with promoting compliance to intervention prescriptions.

Trial registration

ClinicalTrials.gov Identifier: NCT03639350. Registered 21st August 2018—retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00786-3.

Effectiveness of intermittent fasting to potentiate weight loss or muscle gains in humans younger than 60 years old: a systematic review

The aim was to determinate if the intermittent fasting enhances weight loss or muscle gains in humans younger than 60 years old. Multiple databases were searched up to May 2020 for studies in English, using MeSH terms and text words relating intermittent fasting, weight loss and muscle gains. The protocol was registered in PROSPERO. Study quality was assessed using NICE methodology. A total of 10 original articles were evaluated. Eight papers collected data through randomised controlled trials and two from cross-sectional study. Intermittent fasting could be beneficial in resistance trained subjects or in overweight individuals to improve body composition by decreasing fat mass and at least maintain muscle mass; decrease in GLP-1 levels and; improving health-related biomarkers such glucose and insulin levels. However, future studies are needed in order to better elucidate the effect of intermittent fasting on body composition.

Multidimensional Impact of Mediterranean Diet on IBD Patients

BACKGROUND & AIMS

Malnutrition with the accumulation of fat tissue and nonalcoholic fatty liver disease (NAFLD) are conditions associated with inflammatory bowel disease (IBD). Visceral fat and NAFLD-related liver dysfunction can both worsen intestinal inflammation. Because the Mediterranean diet (Md) has been shown to ameliorate both obesity and NAFLD, the aim of this study was to analyze the impact of Md on the nutritional state, liver steatosis, clinical disease activity, and quality of life (QoL) in IBD patients.

METHODS

Patients with IBD, both Crohn's disease (CD) and ulcerative colitis (UC), followed Md for 6 months. Their body mass index (BMI), body tissue composition, liver steatosis and function, serum lipid profile, clinical disease activity, and inflammatory biomarkers (C-reactive protein and fecal calprotectin) were collected at baseline (T0) and compared with those obtained after 6 months (T180) to evaluate the impact of Md.

RESULTS

One hundred forty-two IBD patients, 84 UC and 58 CD, followed Md for 6 months. At T180, diet-adherent CD and UC improved BMI (UC -0.42, P = 0.002; CD -0.48, P = 0.032) and waist circumference (UC -1.25 cm, P = 0.037; CD -1.37 cm, P = 0.041). Additionally, the number of patients affected by liver steatosis of any grade was significantly reduced in both groups (UC T0 31 of 84 [36.9%] vs T180 18 of 84 [21.4%], P = 0.0016; CD T0 27 of 58 [46.6%] vs T180 18 of 58 [31.0%], P < 0.001) after dietary intervention. Finally, after 6 months of the diet, fewer UC and CD patients with stable therapy had active disease (UC T0 14 of 59 [23.7%] vs T180 4 of 59 [6.8%], P = 0.004; CD T0 9 of 51 [17.6%] vs T180 2 of 51 [3.0%], P = 0.011) and elevated inflammatory biomarkers. Mediterranean diet improved QoL in both UC and CD, but neither serum lipid profile nor liver function were modified by the diet.

CONCLUSIONS

A significant reduction of malnutrition-related parameters and liver steatosis was observed in both CD and UC patients after short-term dietary intervention based on the adoption of Md, and this was associated with a spontaneous improvement of disease activity and inflammatory markers.

Diet Quality and Visceral Adiposity among a Multiethnic Population of Young, Middle, and Older Aged Adults

BACKGROUND

Visceral adiposity, more so than overall adiposity, is associated with chronic disease and mortality. There has been, to our knowledge, little research exploring the association between diet quality and visceral adipose tissue (VAT) among a mulitethnic population aged 18-80 y.

OBJECTIVE

The primary objective of this cross-sectional analysis was to examine the association between diet quality [Healthy Eating Index-2010 (HEI-2010) scores] and VAT among a multiethnic population of young, middle, and older aged adults in the United States. Secondary objectives were to repeat these analyses with overall adiposity and blood-based biomarkers for type 2 diabetes and cardiovascular disease risk as outcome measures.

METHODS

A total of 540 adults (dropped out: n = 4; age: 18-40 y, n = 220; 40-60 y, n = 183; 60-80 y, n = 133) were recruited across 3 sites (Honolulu County, San Francisco, and Baton Rouge) for the Shape Up! Adults study. Whole-body DXA, anthropometry, fasting blood draw, and questionnaires (food frequency, physical activity, and demographic characteristics) were completed. Linear regression was used to assess the associations between HEI-2010 tertiles and VAT and secondary outcome measures among all participants and age-specific strata, while adjusting for known confounders.

RESULTS

VAT, BMI (kg/m2), body fat percentage, total body fat, trunk fat, insulin, and insulin resistance were inversely related to diet quality (all P values < 0.004). When stratified by age, diet quality was inversely associated with VAT among participants aged 60-80 y (P < 0.006) and VAT/subcutaneous adipose tissue (SAT) among participants aged 40-60 y (P < 0.008).

CONCLUSIONS

Higher-quality diet was associated with lower VAT, overall adiposity, and insulin resistance among this multiethnic population of young, middle, and older aged adults with ages ranging from 18 to 80 y. More specifically, adherence to a high-quality diet may minimize VAT accumulation in adults aged 60-80 y and preferentially promote storage of SAT compared with VAT in adults aged 40-60 y.This study was registered at clinicaltrials.gov as NCT03637855.