Ketogenic diets, physical activity and body composition: a review

Association between ketogenic diets and depression: A cross-sectional analysis of the NHANES 2005-2023 August

BACKGROUND

The ketogenic diet (KD) is widely used for epilepsy and neurodegenerative diseases. Glutamate, the excitatory neurotransmitter in the body, has been found to be significantly elevated in the brains of some patients with depression. Ketone bodies, the main products of KD, may negatively regulate the metabolic activity of glutamate, which suggests a potential role in the onset and progression of depression. However, the relationship between KD and depression risk remains uncertain.

METHODS

This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and August 2023 to investigate the association between the ketogenic diet ratio (KDR) and depression risk. Multiple logistic regression analysis was employed to examine this association, whereas nonlinear relationships were assessed using restricted cubic splines. Stratification analysis was employed to examine the association between KDR and depression severity. Subgroup analyses were also performed.

RESULTS

In a fully adjusted model accounting for confounding variables, KDR was significantly associated with depression risk. Two-piecewise linear regression analysis better fitted the association (KDR < 0.35, OR: 0.11; 95%CI: 0.03-0.35; P < 0.001). Subgroup analyses indicated that this association between KDR and depression was particularly pronounced in certain specific populations. We further observed a significant correlation between KDR and depression severity (P < 0.001).

CONCLUSION

Higher KDR was associated with a reduced risk of depression, with potentially greater efficacy observed in specific populations. Additionally, KDR has been found to be significantly associated with the severity of depression. Further study could investigate their potential mechanism.

Oxaloacetate and Ketone Bodies Synergistically Promote Myoblast Differentiation in L6 Cells

Malnutrition and aging are major factors that inhibit myoblast differentiation, leading to a decline in muscle function and contributing to sarcopenia development. This study aimed to elucidate the role of nutrients in myoblast differentiation by establishing a culture system at physiological glucose levels and investigating the effects of ketone bodies and oxaloacetate. We successfully cultured myoblasts at physiological glucose concentrations in a hydrophobic membrane filter-equipped culture flask. Under these conditions, ketone bodies and oxaloacetate synergistically upregulated myogenic differentiation markers (Lmod2 and Ckm), indicating enhanced differentiation. Additionally, oxaloacetate upregulated mitochondrial biogenesis markers (mitochondrial DNA copy number and Cs), whereas ketone bodies promoted Akt phosphorylation, a key regulator of differentiation, via the PI3K/Akt/mTOR pathway. These results suggest that the intake of ketone bodies and oxaloacetate effectively prevents sarcopenia by synergistically promoting myoblast differentiation via distinct molecular mechanisms, suggesting a potential new nutritional strategy.

The role of child development and socioeconomic factors in child obesity in Pakistan

This study intricately explores obesity's nexus with socio-emotional, physical development, and socioeconomic status, vital for global public health. It delves into psychological dimensions by scrutinizing attitudes toward obesity and their link with physical development. Additionally, it highlights obesity's physical implications, impacting overall health, chronic conditions, and healthcare systems. Using the Multiple Indicator Cluster Survey (MICS) dataset among 39,168 children aged 30 to 59 months in Pakistan, it examines socioeconomic factors like access to healthy food and parental education. Through logistic regression on diverse demographic samples, this research unveils significant associations between physical development, socio-emotional well-being, demographics, socioeconomic status, and overweight/obesity prevalence. Understanding these connections is crucial for tailored interventions to address escalating obesity rates, requiring nuanced strategies in diverse demographics and socioeconomic contexts.

Anthropometric Trajectories and Dietary Compliance During a Personalized Ketogenic Program

BACKGROUND/OBJECTIVES

Ketogenic diets (KDs) have gained attention for their potential to promote weight loss and metabolic improvements. However, data on long-term body composition changes and adherence rates in real-world settings remain limited.

OBJECTIVE

This study aimed to assess the effects of a personalized ketogenic dietary program on anthropometric parameters over a 9-month period and to evaluate adherence across time.

METHODS

A total of 491 adults participated in a longitudinal intervention involving a structured ketogenic nutrition plan with follow-up at 3, 6, and 9 months. Body weight, fat mass (FM), skeletal muscle mass (SMM), and other composition metrics were measured at each visit.

RESULTS

Significant reductions in body weight (-12.6 kg) and fat mass (-10.3 kg) were observed after 3 months (p < 0.001), with minimal changes at 6 months and partial regain by Month 9. SMM remained relatively stable throughout the study. Retention dropped substantially after 3 months, dropping from 487 to 115 participants at Month 6 and 41 at Month 9. Despite this, participants who completed the program maintained significant anthropometric improvements.

CONCLUSIONS

A well-formulated ketogenic diet may promote rapid fat loss while preserving lean mass in the short term. However, long-term adherence poses significant challenges. Strategies to enhance dietary sustainability and retention are essential for maximizing the benefits of KDs in clinical practice.

The correlation between different lifestyles and body composition focuses on eating habits, nutritional status, and physical exercise components

When it comes to nutritional status and physical performance, body composition is significant. Previous research has shown the correlation between body composition and the mismatch between nutrient intake and requirements. However, this paper aims to evaluate the crucial role of lifestyle factors, such as eating behavior and meal timing, in influencing body composition. Lifestyle variables are important because they affect hormone and growth factor imbalances, which can cause changes in protein synthesis or breakdown, insulin resistance, and overeating. These factors collectively affect muscle mass and fat mass, their influence being consistent across juvenile and adult groups, between men and women. Regarding food preferences, sexual dimorphism of adiposity between men and women seems to be a critical determinant. Additionally, chronic stress leads to emotional eating, while enough sleep plays a big role in affecting growth factors and hormone balances, although the research on this subject is as yet scant. Therefore, understanding and modifying lifestyle habits are essential for the improvement of body composition, irrespective of an individual's gender or age.

Impact of a Fish-Based Restrictive Ketogenic Diet on Body Composition and Strength Capacity: A Pre-Post Study

Background: The ketogenic diet (KD) is becoming a popular nutritional model for athletes. One limitation of this diet is the use of animal-meat products, which may be unacceptable to some people. Moreover, the relationship between this diet's use, body composition, and strength capacity has not been thoroughly investigated. This study aimed to assess the effects of a two-week fish-based restrictive KD on body composition, strength capacity (isometric muscle strength), and somatic disorders in healthy adults. Methods: Participants were recruited through advertisements, posters displayed at the university, and information shared among colleagues. Ultimately, 14 individuals qualified for this study. For two weeks, they followed a designated ketogenic diet enriched with fish and omega-3 fatty acids, with a calorie reduction of -500 kcal/day. The study was designed and conducted as a single-group pre-post study. Before and after completing the diet, participants' body composition (body mass, body fat, fat-free mass, and visceral fat) and strength capacity (knee extensor peak torque [KEPT] and knee flexor peak torque [KFPT]) were measured. The survey also analyzed participants' somatic disorders such as nausea, vomiting, energy level, diarrhea, constipation, drowsiness, sleep problems, hunger, thirst, and bad breath. The average results of both trials obtained before and after the diet were compared using the paired Student's t-test or non-parametric test. The significance level was set at 0.05. Results: After two weeks of a fish-based restrictive KD, significant increases in ketone bodies were observed in both the blood (pre: 0.21 mmol/L ± 0.15 vs. post: 2.20 ± 1.19, p < 0.001) and urine (pre: 0.00 mmol/L ± 0.00 vs. post: 4.64 mmol/L ± 3.24, p < 0.001). Body composition changes included significant reductions in total body mass (pre: 76.66 kg ± 11.06 vs. post: 73.77 kg ± 10.76, p < 0.001), fat mass (pre: 21.34 kg ± 7.36 vs. post: 19.73 kg ± 7.20, p < 0.001), and visceral fat (pre: 708.50 g ± 627.67 vs. post: 603.21 g ± 567.82, p = 0.0012). Skeletal muscle mass decreased by 2% (pre: 27.75 kg ± 5.80 vs. post: 27.03 kg ± 5.47, p = 0.01), though no significant changes were seen in muscle strength when adjusting for body mass or skeletal muscle mass. No major adverse effects were noted in relation to somatic disorders, although some participants reported increased thirst and bad breath. Conclusions: After 14 days of a fish-based restrictive KD, a significant reduction in body mass and changes in body composition were observed, with no loss of muscle strength. This type of diet may serve as an effective method for rapid body mass reduction in sports with weight categories, while preserving muscle strength, which is crucial for athletes. It could also be an alternative means for individuals to eliminate animal meat from their diet.

Food Choice, Nutrition, and Public Health

Maintaining a healthy diet throughout life helps prevent all forms of malnutrition, thereby reducing the risk of non-communicable diseases (NCDs) and related conditions [...].

Can Endogenous or Exogenous Ketosis Tackle the Constraints of Ultraendurance Exercise?

A high-fat, low-carbohydrate, ketogenic diet has appealed to athletes for a long time due to its purported ability to improve exercise performance and postexercise recovery. The availability of ketone supplements has further sparked such interest. The review, therefore, focuses on the potential beneficial impact of exogenous and endogenous ketosis in the context of ultraendurance exercise.

Preliminary Evidence Suggests That a 12-Week Treatment with Tirzepatide Plus Low-Energy Ketogenic Therapy Is More Effective than Its Combination with a Low-Calorie Diet in Preserving Fat-Free Mass, Muscle Strength, and Resting Metabolic Rate in Patients with Obesity

Background: Tirzepatide (TZP), a unimolecular dual agonist targeting glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors, is a promising weight loss agent in obesity. The preservation of metabolically active fat-free mass (FFM), muscle strength (MS), and resting metabolic rate (RMR) is essential for optimizing fat mass (FM) reduction. Although TZP is typically combined with a low-calorie diet (LCD), its impact on FFM is uncertain, and studies on MS and RMR are lacking. Evidence suggests that Low-Energy Ketogenic Therapy (LEKT) may reduce FM while preserving FFM, MS, and RMR. Therefore, this study aimed to compare the effects of an LEKT and an LCD, both combined with TZP, on body weight (BW), FM, FFM, MS, and RMR in patients with obesity. Methods: We prospectively compared the effects of TZP combined with either an LCD or LEKT in 60 patients with obesity (n = 30 per group) over 12 weeks. BW, FM, FFM, MS, and RMR were measured at baseline and after 12 weeks. Clinical parameters, an assessment of dietary compliance, and side effects were also evaluated. Results: At 12-week follow-up, both groups showed a significant BW reduction from baseline (TZP+LEKT, p = 0.0289; TZP+LCD, p = 0.0278), with no significant intergroup difference (p = 0.665). Similarly, FM decreased significantly in both cohorts (TZP+LEKT, p < 0.001; TZP+LCD, p = 0.0185), with the TZP+LEKT group achieving a greater FM loss (p = 0.042). However, the TZP+LCD group exhibited significant declines from baseline in FFM (p = 0.0284), MS (p = 0.0341), and RMR (p < 0.001), whereas we did not observe any significant changes in FFM (p = 0.487), MS (p = 0.691), and RMR (p = 0.263) in the TZP+LEKT group. Intergroup direct comparisons confirmed that the TZP+LCD group experienced significantly greater reductions in FFM (p = 0.0388), MS (p = 0.046), and RMR (p = 0.019). Conclusions: Based on the findings of these preliminary data, we are able to support the hypothesis that TZP+LEKT seems to be superior to TZP+LCD in promoting FM reduction while preserving FFM, MS, and RMR in patients with obesity.

Ketogenic Diets for Body Weight Loss: A Comparison with Other Diets

With the prevalence of obesity and overweight increasing at an alarming rate, more and more researchers are focused on identifying effective weight loss strategies. The ketogenic diet (KD), used as a treatment in epilepsy management for over 100 years, is additionally gaining popularity as a weight loss method. Although its efficacy in weight loss is well documented, the areas where it may be beneficial to other dietary approaches need to be carefully examined. The objective of this paper is to identify the potential benefits of the KD over alternative dietary weight loss strategies based on a comprehensive literature review. It has been shown that the KD may be more bioenergetically efficient than other dietary strategies, inter alia owing to its effect on curtailing hunger, improving satiety and decreasing appetite (influence on hunger and satiety hormones and the sensation of hunger), inducing faster initial weight loss (associated with lower glycogen levels and reduced water retention), and controlling glycaemia and insulinemia (directly attributable to the low-carbohydrate nature of KD and indirectly to the other areas described). These effects are accompanied by improved insulin sensitivity, reduced inflammation (through ketone bodies and avoidance of pro-inflammatory sugars), reduced need for pharmacological obesity control (the diet's mechanisms are similar to those of medication but without the side effects), and positive impacts on psychological factors and food addiction. Based on the authors' review of the latest research, it is reasonable to conclude that, due to these many additional health benefits, the KD may be advantageous to other diet-based weight loss strategies. This important hypothesis deserves further exploration, which could be achieved by including outcome measures other than weight loss in future clinical trials, especially when comparing different diets of equal caloric value.

Body Fat and Visceral Fat Values in Spanish Healthcare Workers: Associated Variables

BACKGROUND/OBJECTIVES

Excessive body adiposity is a significant public health challenge on a global scale. This study aimed to investigate the association between various sociodemographic factors and healthy lifestyle habits and the presence or absence of elevated body adiposity levels.

METHODOLOGY

Two studies were conducted, a retrospective longitudinal study and a cross-sectional descriptive study. The analysis included 44,939 healthcare workers, categorised into four professional groups, to explore the relationship between age, sex, smoking, physical activity, and adherence to the Mediterranean diet and body adiposity, assessed as elevated body fat (BF) and visceral fat (VF) levels. Descriptive statistics encompassed categorical and quantitative variables, analysed using frequencies, Student's t-tests, chi-square tests, and multinomial logistic regression models. Associations, concordances, and correlations were further examined using logistic regression and Cohen's and Pearson's kappa coefficients.

RESULTS

Age, sex, and physical activity were the factors most strongly associated with elevated BF and VF levels. Odds ratios (ORs) indicated the following significant associations: individuals aged 60 years and older exhibited ORs of 6.71 (95% CI: 5.68-7.74) for BF and 12.18 (95% CI: 10.01-14.26) for VF; male sex was associated with ORs of 2.21 (95% CI: 2.06-2.36) for BF and 12.51 (95% CI: 11.29-13.74) for VF. Sedentary behaviour was linked to ORs of 3.69 (95% CI: 3.41-3.97) for BF and 4.20 (95% CI: 3.78-4.63) for VF. Among healthcare professionals, nursing assistants and orderlies demonstrated the highest levels of adipose tissue accumulation.

CONCLUSIONS

Elevated BF and VF levels among healthcare personnel are significantly associated by lifestyle factors, sex, and age, with the most pronounced risk observed in nursing assistants and orderlies. Further research focusing on the causal relationships between lifestyle behaviours and adiposity in this population will provide valuable insights and support the design of targeted preventive strategies to mitigate its prevalence.

Evaluating the differential benefits of varying carbohydrate-restricted diets on lipid profiles and cardiovascular risks in dyslipidemia: a meta-analysis and systematic review

Background: carbohydrate-restricted diets (CRDs) have gained attention to address metabolic dysregulation commonly observed in dyslipidemia, a condition posing significant risks to cardiovascular health. However, the effectiveness of CRDs in improving cardiovascular health remains contentious. This meta-analysis comprehensively evaluated the long-term effects of CRDs on glucolipid metabolism and weight loss in individuals with dyslipidemia. Methods: extensive searches were conducted in PubMed, Web of Science, Scopus, the Cochrane Library, and EMBASE. Randomized controlled trials examining the effects of CRDs on glucolipid metabolism and weight loss in adults with dyslipidemia over a minimum of three weeks were included. This analysis compared the differential effects between moderate-low carbohydrate diets (MLCDs) and low carbohydrate diets (LCDs), including a targeted evaluation of animal-based CRDs and dyslipidemic individuals based on the BMI status, thereby addressing gaps in current knowledge. Results: Our findings indicated that CRDs significantly enhanced lipid profiles, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and apolipoprotein B (ApoB), and contributed to weight management in individuals with dyslipidemia. MLCDs were more effective than LCDs in improving all lipid profiles except for TG, which was more effectively managed by LCDs. Animal-based CRDs did not significantly impact lipid profiles. Dyslipidemic individuals with overweight and obesity showed significant changes in TG and ApoB. A noteworthy negative correlation was also observed between TC, TG, and low-density lipoprotein cholesterol levels with higher dietary fiber intake, supporting the beneficial impact of fiber on cardiovascular health. Conclusions: These results for the first time highlighted the potential of adopting MLCDs, particularly those with sufficient fiber content, as a powerful strategy for reducing the risk of cardiovascular diseases in patients suffering from dyslipidemia.

How exercise frequency affects BMI: a nationwide cross-sectional study exploring key influencing factors, including dietary behavior

Purpose

Body Mass Index (BMI) is an important indicator for assessing obesity and related health risks. With the rapid socio-economic development and changes in lifestyle, abnormal BMI (such as underweight, overweight, and obesity) has become an increasingly serious public health issue. This study aims to explore the impact of exercise frequency on BMI among Chinese adults aged 19 to 59, and to analyze the role of dietary behaviors in regulating BMI, providing a basis for BMI intervention strategies.

Method

The study employs a multi-stage sampling method across 23 provinces, provincial capitals, and four municipalities in China, randomly selecting 120 cities from each region. Online surveys were conducted using Wenjuanxing by trained surveyors.

Result

A total of 8,611 individuals participated in the survey. Among them, 1,066 (12.38%) had a BMI < 18.5, 5,354 (62.18%) had a BMI between 18.5 and 23.9, and 2,191 (25.44%) had a BMI ≥ 24. Factors such as gender, age, marital status, monthly household income, smoking, and alcohol consumption significantly affected BMI (p < 0.05). The overall impact of exercise on abnormal BMI was -0.003, with a direct effect of -0.005. The mediating effect of dietary behaviors between exercise and abnormal BMI was 0.002, accounting for 92.48% of the total effect.

Conclusion

This study highlights the widespread prevalence of abnormal BMI among individuals aged 19 to 59 in China. A single exercise intervention may be insufficient to effectively improve abnormal BMI; thus, it should be combined with strategies aimed at enhancing dietary behaviors.

Exploring the effect of different diet types on ageing and age-related diseases

In recent times, there has been growing interest in understanding the factors contributing to prolonged and healthy lifespans observed in specific populations, tribes, or countries. Factors such as environmental and dietary play significant roles in shaping the ageing process and are often the focus of inquiries seeking to unravel the secrets behind longevity. Among these factors, diet emerges as a primary determinant, capable of either promoting or mitigating the onset of age-related diseases that impact the ageing trajectory. This review examines the impact of various diet types on ageing and age-related conditions, including cardiovascular disease, cancer, neurodegenerative disorders, and metabolic syndrome. Different dietary patterns, such as the Mediterranean diet, the Japanese diet, vegetarian and vegan diets, as well as low-carbohydrate and ketogenic diets, are evaluated for their potential effects on longevity and health span. Each diet type is characterized by distinct nutritional profiles, emphasizing specific food groups, macronutrient compositions, and bioactive components, which may exert diverse effects on ageing processes and disease risk. Additionally, dietary factors such as calorie restriction, intermittent fasting, and dietary supplementation are explored for their potential anti-ageing and disease-modifying effects. Understanding the influence of various diet types on ageing and age-related diseases can inform personalized dietary recommendations and lifestyle interventions aimed at promoting healthy aging and mitigating age-associated morbidities.

Ketogenic diet as a therapeutic approach in autism spectrum disorder: a narrative review

The ketogenic diet (KD) originated in the 1920s. It is a dietary model that is low in carbohydrates, adequate in protein, and high in fat content. The diet mimics starvation and increases the production of ketone bodies, leading to ketosis in metabolism. KD is used as an anticonvulsant treatment approach in patients with drug-resistant epilepsy. In addition, it is thought that a KD may have therapeutic potential in the treatment of neurological disorders, including autism spectrum disorders (ASD). Numerous recent studies have demonstrated that a KD can improve behavioural parameters in individuals with ASD. This review aims to address the potential mechanisms of action of the KD and to examine the effects of the KD on individuals diagnosed with ASD. It is likely that this role is mediated through improvements in energy metabolism, reduction of pro-inflammatory cytokine levels, control of neurotransmitters, gene expression and modulation of the gut microbiota. Based on the available evidence, a KD appears to be a safe and effective treatment for ASD.

A Comprehensive Overview of the Current Status and Advancements in Various Treatment Strategies against Epilepsy

Epilepsy affects more than 70 million individuals of all ages worldwide and remains one of the most severe chronic noncommunicable neurological diseases globally. Several neurotransmitters, membrane protein channels, receptors, enzymes, and, more recently noted, various pathways, such as inflammatory and mTORC complexes, play significant roles in the initiation and propagation of seizures. Over the past two decades, significant developments have been made in the diagnosis and treatment of epilepsy. Various pharmacological drugs with diverse mechanisms of action and other treatment options have been developed to control seizures and treat epilepsy. These options include surgical treatment, nanomedicine, gene therapy, natural products, nervous stimulation, a ketogenic diet, gut microbiota, etc., which are in various developmental stages. Despite a plethora of drugs and other treatment options, one-third of affected individuals are resistant to current medications, while the majority of approved drugs have severe side effects, and significant changes can occur, such as pharmacoresistance, effects on cognition, long-term problems, drug interactions, risks of poor adherence, specific effects for certain medications, and psychological complications. Therefore, the development of new drugs and other treatment options that have no or minimal adverse effects is needed to combat this deadly disease. In this Review, we comprehensively summarize and explain all of the treatment options that have been approved or are in developmental stages for epilepsy as well as their status in clinical trials and advancements.

Nutritional management and autism spectrum disorder: A systematic review

BACKGROUND

Autism spectrum disorder (ASD) presents unique challenges related to feeding and nutritional management. Children with ASD often experience feeding difficulties, including food selectivity, refusal, and gastrointestinal issues. Various interventions have been explored to address these challenges, including dietary modifications, vitamin supplementation, feeding therapy, and behavioral interventions.

AIM

To provide a comprehensive overview of the current evidence on nutritional management in ASD. We examine the effectiveness of dietary interventions, vitamin supplements, feeding therapy, behavioral interventions, and mealtime practices in addressing the feeding challenges and nutritional needs of children with ASD.

METHODS

We systematically searched relevant literature up to June 2024, using databases such as PubMed, PsycINFO, and Scopus. Studies were included if they investigated dietary interventions, nutritional supplements, or behavioral strategies to improve feeding behaviors in children with ASD. We assessed the quality of the studies and synthesized findings on the impact of various interventions on feeding difficulties and nutritional outcomes. Data extraction focused on intervention types, study designs, participant characteristics, outcomes measured, and intervention effectiveness.

RESULTS

The review identified 316 studies that met the inclusion criteria. The evidence indicates that while dietary interventions and nutritional supplements may offer benefits in managing specific symptoms or deficiencies, the effectiveness of these approaches varies. Feeding therapy and behavioral interventions, including gradual exposure and positive reinforcement, promise to improve food acceptance and mealtime behaviors. The findings also highlight the importance of creating supportive mealtime environments tailored to the sensory and behavioral needs of children with ASD.

CONCLUSION

Nutritional management for children with ASD requires a multifaceted approach that includes dietary modifications, supplementation, feeding therapy, and behavioral strategies. The review underscores the need for personalized interventions and further research to refine treatment protocols and improve outcomes. Collaborative efforts among healthcare providers, educators, and families are essential to optimize this population's nutritional health and feeding practices. Enhancing our understanding of intervention sustainability and long-term outcomes is essential for optimizing care and improving the quality of life for children with ASD and their families.

The effects of portfolio moderate-carbohydrate and ketogenic diets on anthropometric indices, metabolic status, and hormonal levels in overweight or obese women with polycystic ovary syndrome: a randomized controlled trial

BACKGROUND

Polycystic Ovary Syndrome (PCOS) is one of the most common hormonal disorders in reproductive-age women caused by hyperinsulinemia. The portfolio Moderate-carbohydrate diet (PMCD) is a plant-based diet with a carbohydrate content of 40% and incorporates five cholesterol-lowering foods. While, the ketogenic diet is a high-fat diet with 70% fat, promoting a ketosis state. To the best of our knowledge, no study compared the therapeutic effects of these two diets in PCOS patients. Thus, this study aimed to compare the impact of PLCD and KD on anthropometric indices, metabolic status, and hormonal levels in overweight or obese women with PCOS.

METHODS

This open-label, randomized clinical trial was conducted on forty-six PCOS women. 21 women in PMCD and 19 in the KD group completed the study. The anthropometric indices including body mass index (BMI) and fat body mass (FBM), metabolic markers (fasting blood glucose (FBG)) and plasma lipid profiles including low-density lipoprotein (LDL), triglycerides, and high-density lipoproteins (HDL) were measured. Reproductive hormones such as luteinizing hormone (LH), dehydroepiandrosterone sulfate (DHEA-s) and free testosterone were assessed at the baseline and after the intervention.

RESULTS

However, after 8 weeks both diets demonstrated enhancement in anthropometric indices (BMI, FBM, lean body mass), metabolic status (FBG, insulin serum levels), and reproductive hormones such as LH, free testosterone, and DHEA-s. The mean difference in the KD improved more than the PMCD in the field of BMI reduction (MD (SD) 2.73 (0.351) vs. MD (SD) 1.71 (0.775)) and LH (MD 4.13 (1.375) vs.MD 2.46 (1.105)). Nevertheless, the lipid profile including LDL-C and triglycerides improved more in the PMCD compared to the KD (MD 33.95 (7.345) vs. MD 23.34 (14.136)) and (MD 38.20 (10.757) vs. MD 57.62 (21.688)) respectively. There were no significant changes in the Ferriman-Gallwey score within or between the two groups.

CONCLUSION

The findings revealed that both diets were effective in improving PCOS manifestations. However, the KD exhibited greater effectiveness in enhancing body measurements, metabolic factors, and reproductive hormone levels compared to the PMCD in obese PCOS women. Furthermore, PMCD could be more beneficial for PCOS women with lipide disorders.

REGISTRATION NUMBER OF CLINICAL TRIAL

IRCT20200912048693N3, Trial registered 2022-12-14. https://www.irct.ir/trial/67548.

Effect of Different Dietary Patterns on Cardiometabolic Risk Factors: An Umbrella Review of Systematic Reviews and Meta-Analyses

BACKGROUND/OBJECTIVES

Lifestyle interventions such as dietary changes have been proposed to control the cardiometabolic risk factors and thus prevent cardiovascular (CV) disease (CVD). We performed an umbrella review to investigate whether different dietary patterns affect CV risk in individuals with at least one cardiometabolic risk factor (hypertension, dyslipidemia, obesity, diabetes, metabolic syndrome) but not established CVD.

METHODS

We systematically searched the PubMed and Scopus databases (up to August 2024) for the systematic reviews and meta-analyses of randomized controlled trials (RCTs). Articles should be written in English and refer to a specific dietary pattern (such as Mediterranean diet, etc.). The population studied referred to adults with at least one cardiovascular (CV) risk factor.

RESULTS

From 4512 records identified, we finally included 25 meta-analyses with a total of 329 associations. Strong evidence for a benefit was found for LCD with reductions in BW [MD: -4.79 (95% CI -5.85, -3.72) kg, p ≤ 0.001], SBP [MD: -6.38 (95% CI -7.84, -4.93) mmHg, p ≤ 0.001], TG [WMD: -5.81 (95% CI -7.96, -3.66) mg/dL, p ≤ 0.001], and fasting plasma insulin [MD: -15.35 (95% CI -19.58, -11.12) pmol/L, p ≤ 0.001], as well as for low-GI diet for the reduction of BW [SMD: -0.66 (95% CI -0.90, -0.43) kg, p ≤ 0.001].

CONCLUSIONS

Across many dietary patterns, LCD showed strong or highly suggestive evidence for a benefit on SBP, BW reduction, and lipid profile improvement. Secondarily, low-GI, DASH, and Portfolio and Nordic diets suggested beneficial effects on controlling CV risk.

The effect of a low-carbohydrate diet on subcutaneous adipose tissue in females with lipedema

Introduction

Lipedema is a common, yet underdiagnosed, subcutaneous adipose tissue (SAT) disorder. The main characteristics are SAT expansion in the lower extremities and arms, pain, and tenderness to palpation. It remains unknown if a low-carbohydrate diet (LCD) influences SAT in females with lipedema.

Objectives

To evaluate the effect of a LCD low-energy diet, compared to a low-fat isoenergetic control diet, on calf subcutaneous adipose tissue area, muscle area, SAT/muscle ratio, calf circumference and body composition in females with lipedema.

Subjects/methods

Adult females with obesity and lipedema were randomized to 1,200 kcal/day diets, either LCD or control (75 and 180 g/day of carbohydrates, respectively) for 8 weeks. Body composition was measured with bioelectrical impedance analysis, calf SAT area, muscle area, and circumference with magnetic resonance imaging and pain with brief pain inventory, before and after the intervention.

Results

Thirteen participants were included (five in the LCD group), with a mean age of 46 ± 12 years and a BMI of 37 ± 6 kg/m2. A significant reduction in calf SAT area, calf circumference, and pain was observed in the LCD group only. Both LCD and control groups experienced a significant reduction body weight, fat mass, fat free mass, and muscle area, with no differences between groups. No significant changes over time were found for SAT/muscle ratio.

Conclusion

A LCD has the potential to reduce SAT and pain in females with lipedema, despite a reduction in muscle mass in lipedema affected areas in both diet groups. Further studies are needed to confirm these findings and explore potential mechanisms.

Clinical trial registration

NCT04632810: Effect of ketosis on pain and quality of life in patients with lipedema (Lipodiet). https://clinicaltrials.gov/study/NCT04632810.

Ketogenic diet in clinical populations-a narrative review

Ketogenic diet (KD) is a high-fat, low-carbohydrate (CHO) diet, designed to induce a metabolic state of ketosis in which the body metabolizes primarily lipids for energy production. Various forms of KD are being promoted as promising treatments for numerous health conditions from chronic headaches to weight-loss and even different forms of cancer and are becoming increasingly more popular. KD appears to be an efficacious approach for weight-loss, and maintenance, improved glycemia, cognitive function and cancer prognosis. However, there is a controversy regarding the safety of KD, and the potential health risks that might be associated with long-term exposure to KD. There is a gap between the acceptance and utilization of KD in individuals with health conditions and the criticism and negative attitudes toward KD by some clinicians. Many individuals choose to follow KD and are encouraged by the positive results they experience. Although the medical establishment does not endorse KD as a first line of treatment, clinicians need to be informed about KD, and offer support and medical supervision for patients who self-select to follow KD. This can ensure that within the boundaries of KD, patients will make good and healthy dietary choices and prevent clinical disengagement in extreme cases. To that end, there is an urgent need for good quality research to address the issues of long-term safety of KD in different clinical populations and for standardization of KD both in research and in the clinic.

Is a Meta-Analysis of Clinical Trial Outcomes for Ketogenic Diets Justifiable? A Critical Assessment Based on Systematic Research

While the macronutrient content of a ketogenic diet specifically utilized for childhood epilepsy is clearly defined in the literature, variations among other ketogenic diets exhibit substantial heterogeneity. Furthermore, studies utilizing ketogenic diets contain several confounders with notable impacts on outcomes, thereby rendering both their findings and those of the meta-analyses less reliable. The objective of this meta-epidemiological assessment was to scrutinize existing clinical trials that investigated the effects of ketogenic diets on patients with obesity and diabetes, thereby determining the feasibility of conducting a meta-analysis. The Ovid Medline, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase databases were searched from 1946 to 24 September 2024. Of the studies reviewed, none met the predefined inclusion criteria. However, seven articles met these criteria very closely. In the future, studies investigating the effects of ketogenic diets containing significant confounding factors should adopt a single definition of a ketogenic diet. Additionally, accurate measurement of actual macronutrient and caloric intake, along with regularly monitored nutritional ketosis, will be essential to highlight the true effects of a ketogenic diet.

Effect of ketogenic diets on lipid metabolism in adults: protocol for a systematic review

INTRODUCTION

The ketogenic diet is a very low carbohydrate diet known for its ability to reduce weight and counteract hyperglycaemia. However, ketogenic diets recommend an increased intake of fats, raising concerns about cardiometabolic risk in adults. Due to the higher intake of fats in the ketogenic diet, there is significant variability in outcomes of lipid metabolism in the population. Interventions have reported improvements in lipid profile while other studies did not find changes, and there are reports of increased low density lipoprotein (LDL) and triglyceride values. Hence, this is a protocol for a systematic review of the published literature and a summary of the effect of ketogenic diets on lipid metabolism in adults.

METHODS AND ANALYSIS

Five databases (PubMed, Embase, Scopus, Cochrane Library and Web of Science) will be searched for studies on ketogenic diets in adult populations. Studies will be included if they report results from ketogenic diet interventions among adults. Exclusion is populations with diagnosed neurological disorders. Two reviewers will independently screen retrieved citations, extract data and appraise the risk of bias. Quantitative estimates (eg, standardised mean difference) measuring the change in the total cholesterol, LDL and triglyceride concentration will be pooled using random effects meta-analysis to produce one summarised weighted estimate. Sources of heterogeneity will be explored using subgroup analysis. This protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis for Protocols (PRISMA), and the final review will be reported following the PRISMA 2020 guidelines.

ETHICS AND DISSEMINATION

The present protocol and the systematic review to be carried out do not require ethics clearance. The data source will be published studies. This review will provide estimates to inform the public about the effect of ketogenic diets on lipid metabolism and the possible peril of increasing cardiometabolic risk. The results will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022309665.

Problems and Opportunities in the use of Bioelectrical Impedance Analysis for Assessing Body Composition During Ketogenic Diets: A Scoping Review

PURPOSE OF THE REVIEW

The use of bioelectrical impedance analysis (BIA) for monitoring body composition during the ketogenic diet has experienced a rapid surge. This scoping review aimed to assess the validity of procedures applying BIA in the ketogenic diet and to suggest best practices for optimizing its utilization.

RECENT FINDINGS

We conducted a systematic scoping review of peer-reviewed literature involving BIA for assessing body composition in individuals adhering to a ketogenic diet. Searches of international databases yielded 1609 unique records, 72 of which met the inclusion criteria and were reviewed. Thirty-five studies used foot-to-hand technology, 34 used standing position technology, while 3 did not declare the technology used. Raw bioelectrical parameters were reported in 21 studies. A total of 196 body mass components were estimated, but predictive equations were reported in only four cases. Most research on BIA during ketogenic diets did not report the equations used for predicting body composition, making it impossible to assess the validity of BIA outputs. Furthermore, the exceedingly low percentage of studies reporting and analyzing raw data makes it challenging to replicate methodologies in future studies, highlighting that BIA is not being utilized to its full potential. There is a need for more precise technology and device characteristics descriptions, full report of raw bioelectrical data, and predictive equations utilized. Moreover, evaluating raw data through vectorial analysis is strongly recommended. Eventually, we suggest best practices to enhance BIA outcomes during ketogenic diets.

Nutritional Considerations During Major Weight Loss Therapy: Focus on Optimal Protein and a Low-Carbohydrate Dietary Pattern

PURPOSE OF REVIEW

Considering the high prevalence of obesity and related metabolic impairments in the population, the unique role nutrition has in weight loss, reversing metabolic disorders, and maintaining health cannot be overstated. Normal weight and well-being are compatible with varying dietary patterns, but for the last half century there has been a strong emphasis on low-fat, low-saturated fat, high-carbohydrate based approaches. Whereas low-fat dietary patterns can be effective for a subset of individuals, we now have a population where the vast majority of adults have excess adiposity and some degree of metabolic impairment. We are also entering a new era with greater access to bariatric surgery and approval of anti-obesity medications (glucagon-like peptide-1 analogues) that produce substantial weight loss for many people, but there are concerns about disproportionate loss of lean mass and nutritional deficiencies.

RECENT FINDINGS

No matter the approach used to achieve major weight loss, careful attention to nutritional considerations is necessary. Here, we examine the recent findings regarding the importance of adequate protein to maintain lean mass, the rationale and evidence supporting low-carbohydrate and ketogenic dietary patterns, and the potential benefits of including exercise training in the context of major weight loss. While losing and sustaining weight loss has proven challenging, we are optimistic that application of emerging nutrition science, particularly personalized well-formulated low-carbohydrate dietary patterns that contain adequate protein (1.2 to 2.0 g per kilogram reference weight) and achieve the beneficial metabolic state of euketonemia (circulating ketones 0.5 to 5 mM), is a promising path for many individuals with excess adiposity.

Efficacy and tolerability of classical and polyunsaturated fatty acids ketogenic diet in controlling paediatric refractory epilepsy - A randomized study

OBJECTIVES

To measure and compare the efficacy and tolerability of a classical ketogenic diet (CKD) and a polyunsaturated fatty acids ketogenic diet (PUFAKD) in managing childhood refractory epilepsy. Efficacy was assessed by measuring the change in seizure frequency at 3, 6, 9, and 12 months within and between groups. The percentage reduction in seizures at <50 %, 50-90 %, >90 %, and 100 % was also measured. Tolerability was assessed and compared by recording adverse events - vomiting, nausea, lethargy, and constipation.

METHODS

52 children, aged 2-10 years, were randomized, 25 in the CKD group and 27 in the PUFAKD group. Fat: carbohydrate + protein ratio of 2.2:1-4:1 was maintained in both diets; the PUFAKD group only used unsaturated fats with an omega 3: omega 6 ratio of 1:2.8. Ketone levels were measured using keto-dipsticks, with 4+ and 4++ (80-160 mg/dL) being the most optimal values.

RESULTS

A significant decrease (p=0.001) in seizures was observed (n=52), with no significant difference (p=0.537) between the two groups. The mean seizure reduction was 71.1 %, with no significant difference (p=0.488) in both groups. The mean compliance rate was 78.3 % (n=52). A statistically significant linear trend existed between a higher compliance rate and a greater reduction in seizures (p = 0.042, Z=4.039) among all children (n=52). Nausea (p=0.033) and vomiting (p=0.014) occurred more in PUFAKD than in CKD.

CONCLUSION

No significant difference was seen in seizure reduction between the two groups. Compliance correlates with a greater seizure reduction. Despite similar seizure reduction rates, the novel PUFAKD exhibited poorer compliance and more pronounced adverse effects compared to CKD. CKD remained a superior choice over the novel PUFAKD in the management of paediatric refractory epilepsy. More controlled trials with varying PUFA compositions are recommended for long-term evaluations.

Digesting the complex metabolic effects of diet on the host and microbiome

The past 50 years of interdisciplinary research in humans and model organisms has delivered unprecedented insights into the mechanisms through which diet affects energy balance. However, translating these results to prevent and treat obesity and its associated diseases remains challenging. Given the vast scope of this literature, we focus this Review on recent conceptual advances in molecular nutrition targeting the management of energy balance, including emerging dietary and pharmaceutical interventions and their interactions with the human gut microbiome. Notably, multiple current dietary patterns of interest embrace moderate-to-high fat intake or prioritize the timing of eating over macronutrient intake. Furthermore, the rapid expansion of microbiome research findings has complicated multiple longstanding tenets of nutrition while also providing new opportunities for intervention. Continued progress promises more precise and reliable dietary recommendations that leverage our growing knowledge of the microbiome, the changing landscape of clinical interventions, and our molecular understanding of human biology.

Ketone bodies in cell physiology and cancer

Ketogenic diets (KDs), fasting, or prolonged physical activity elevate serum ketone bodies (KBs) levels, providing an alternative fuel source for the brain and other organs. However, KBs play pleiotropic roles that go beyond their role in energy production. KBs can act as signaling metabolites, influence gene expression, proteins' posttranslational modifications (PTMs), inflammation, and oxidative stress. Here, we explore the impact of KBs on mammalian cell physiology, including aging and tissue regeneration. We also concentrate on KBs and cancer, given the extensive evidence that dietary approaches inducing ketosis, including fasting-mimicking diets (FMDs) and KDs, can prevent cancer and affect tumor progression.

Genetics of Exercise and Diet-Induced Fat Loss Efficiency: A Systematic Review

Physical exercise and dieting are well-known and effective methods for fat loss and improving cardiovascular health. However, different individuals often react differently to the same exercise regimen or dietary plan. While specific individuals may undergo substantial fat loss, others may observe only limited effects. A wide range of inter-individual variability in weight gain and changes in body composition induced by physical exercises and diets led to an investigation into the genetic factors that may contribute to the individual variations in such responses. This systematic review aimed at identifying the genetic markers associated with fat loss resulting from diet or exercise. A search of the current literature was performed using the PubMed database. Forty-seven articles met the inclusion criteria when assessing genetic markers associated with weight loss efficiency in response to different types of exercises and diets. Overall, we identified 30 genetic markers of fat-loss efficiency in response to different kinds of diets and 24 in response to exercise. Most studies (n = 46) used the candidate gene approach. We should aspire to the customized selection of exercise and dietary plans for each individual to prevent and treat obesity.

The effects of conjugated linoleic acid supplementation on anthropometrics and body composition indices in adults: a systematic review and dose-response meta-analysis

Prior meta-analytic investigations over a decade ago rather inconclusively indicated that conjugated linoleic acid (CLA) supplementation could improve anthropometric and body composition indices in the general adult population. More recent investigations have emerged, and an up-to-date systematic review and meta-analysis on this topic must be improved. Therefore, this investigation provides a comprehensive systematic review and meta-analysis of randomised controlled trials (RCT) on the impact of CLA supplementation on anthropometric and body composition (body mass (BM), BMI, waist circumference (WC), fat mass (FM), body fat percentage (BFP) and fat-free mass (FFM)) markers in adults. Online databases search, including PubMed, Scopus, the Cochrane Library and Web of Science up to March 2022, were utilised to retrieve RCT examining the effect of CLA supplementation on anthropometric and body composition markers in adults. Meta-analysis was carried out using a random-effects model. The I2 index was used as an index of statistical heterogeneity of RCT. Among the initial 8351 studies identified from electronic databases search, seventy RCT with ninety-six effect sizes involving 4159 participants were included for data analyses. The results of random-effects modelling demonstrated that CLA supplementation significantly reduced BM (weighted mean difference (WMD): -0·35, 95 % CI (-0·54, -0·15), P < 0·001), BMI (WMD: -0·15, 95 % CI (-0·24, -0·06), P = 0·001), WC (WMD: -0·62, 95% CI (-1·04, -0·20), P = 0·004), FM (WMD: -0·44, 95 % CI (-0·66, -0·23), P < 0·001), BFP (WMD: -0·77 %, 95 % CI (-1·09, -0·45), P < 0·001) and increased FFM (WMD: 0·27, 95 % CI (0·09, 0·45), P = 0·003). The high-quality subgroup showed that CLA supplementation fails to change FM and BFP. However, according to high-quality studies, CLA intake resulted in small but significant increases in FFM and decreases in BM and BMI. This meta-analysis study suggests that CLA supplementation may result in a small but significant improvement in anthropometric and body composition markers in an adult population. However, data from high-quality studies failed to show CLA's body fat-lowering properties. Moreover, it should be noted that the weight-loss properties of CLA were small and may not reach clinical importance.

Nutrition and dietary restrictions in cancer prevention

The composition and pattern of dietary intake have emerged as key factors influencing aging, regeneration, and consequently, healthspan and lifespan. Cancer is one of the major diseases more tightly linked with aging, and age-related mortality. Although the role of nutrition in cancer incidence is generally well established, we are far from a consensus on how diet influences tumour development in different tissues. In this review, we will discuss how diet and dietary restrictions affect cancer risk and the molecular mechanisms potentially responsible for their effects. We will cover calorie restriction, intermittent fasting, prolonged fasting, fasting-mimicking diet, time-restricted eating, ketogenic diet, high protein diet, Mediterranean diet, and the vegan and vegetarian diets.

Body Fat Depletion: the Yin Paradigm for Treating Type 2 Diabetes

PURPOSE OF REVIEW

To highlight that body fat depletion (the Yin paradigm) with glucose-lowering treatments (the Yang paradigm) are associated with metabolic benefits for patients with type 2 diabetes mellitus (T2DM).

RECENT FINDINGS

The sodium-glucose cotransporter-2 inhibitor-mediated sodium/glucose deprivation can directly improve glycemic control and kidney outcome in patients with T2DM. The glucose deprivation might also promote systemic fatty acid β-oxidation to deplete ectopic/visceral fat and thereby contribute to the prevention of cardiovascular diseases. As with metabolic surgery, bioengineered incretin-based medications with potent anorexigenic and insulinotropic efficacy can significantly reduce blood glucose as well as body weight (especially in the ectopic/visceral fat depots). The latter effects could be a key contributor to their cardiovascular-renal protective effects. In addition to a healthy diet, the newer glucose-lowering medications, with body fat reduction effects, should be prioritized when treating patients with T2DM, especially for those with established cardiovascular/renal risks or diseases.

The effects of beetroot and nitrate supplementation on body composition: a GRADE-assessed systematic review and meta-analysis

This systematic review and meta-analysis aimed to investigate the effects of beetroot (BR) or nitrate supplements on body composition indices. A systematic search was conducted for randomised controlled trials (RCT) published up to August 2022 among online databases including Scopus, PubMed/Medline, Web of Science and Embase. Meta-analyses were carried out using a random-effects model. The I2 index was used to assess the heterogeneity of RCT. A total of twelve RCT met the inclusion criteria for this meta-analysis. The pooled effect size of included studies indicated that BR or nitrate supplementation did not change body weight (weighted mean differences (WMD): -0·14 kg, 95 % CI -1·22, 1·51; P = 0·836; I2 = 0 %), BMI (WMD: -0·07 kg/m2, 95 % CI -0·19,0·03; P = 0·174, I2 = 0 %), fat mass (WMD: -0·26 kg, 95 % CI -1·51, 0·98; P = 0·677, I2 = 0 %), waist circumference (WMD: -0·28 cm, 95 % CI -2·30, 1·74; P = 0·786, I2 = 0 %), body fat percentage (WMD: 0·18 %, 95 % CI -0·62, 0·99; P = 0·651, I2 = 0 %), fat-free mass (WMD: 0·31 kg, 95 % CI -0·31, 1·94; P = 0·703, I2 = 0 %) and waist-to-hip ratio (WMD: 0, 95 % CI -0·01, 0·02; P = 0·676, I2 = 0 %). Subgroup analyses based on trial duration, BR or nitrate dose, study design, baseline BMI and athletic status (athlete v. non-athlete) demonstrated similar results. Certainty of evidence across outcomes ranged from low to moderate. This meta-analysis study suggests that BR or nitrate supplements cannot efficiently ameliorate body composition indices regardless of supplement dosage, trial duration and athletic status.

Molecular Study of the Protective Effect of a Low-Carbohydrate, High-Fat Diet against Brain Insulin Resistance in an Animal Model of Metabolic Syndrome

Brain insulin resistance is linked to metabolic syndrome (MetS). A low-carbohydrate, high-fat (LCHF) diet has been proposed to have a protective effect. Therefore, this study aimed to investigate the brain insulin resistance markers in a rat animal model of MetS and the protective effects of the LCHF diet. Four groups of male rats (10/group) were created. Group I (Control) was fed a regular diet. Groups II-IV were injected with dexamethasone (DEX) to induce MetS. Group II received DEX with a regular diet. Group III (DEX + LCHF) rates were fed a low-carbohydrate, high-fat diet, while Group IV (DEX + HCLF) rats were fed a high-carbohydrate, low-fat (HCLF) diet. At the end of the four-week experiment, HOMA-IR was calculated. Moreover, cerebral gene expression analysis of S-100B, BDNF, TNF-α, IGF-1, IGF-1 R, IGFBP-2, IGFBP-5, Bax, Bcl-2, and caspase-3 was carried out. In the DEX group, rats showed a significant increase in the HOMA-IR and a decrease in the gene expression of IGF-1, IGF-1 R, IGFBP-2, IGFBP-5, BDNF, and Bcl2, with a concomitant rise in S100B, TNF-α, Bax, and caspase-3. The LCHF diet group showed a significantly opposite effect on all parameters. In conclusion, MetS is associated with dysregulated cerebral gene expression of BDNF, S100B, and TNF-α and disturbed IGF-1 signaling, with increased apoptosis and neuroinflammation. Moreover, the LCHF diet showed a protective effect, as evidenced by preservation of the investigated biochemical and molecular parameters.

The effect of dietary carbohydrate restriction and aerobic exercise on retinol binding protein 4 (RBP4) and fatty acid binding protein 5 (FABP5) in middle-aged men with metabolic syndrome

Exercise and dietary interventions have been described to positively affect metabolic syndrome (MetS) via molecular-induced changes. The purpose of this study was to investigate the effects of dietary carbohydrate restriction and aerobic exercise (AE) on retinol binding protein 4 (RBP4) and fatty acid binding protein 5 (FABP5) in middle-aged men with MetS. The study had a randomised, double-blinded, parallel-controlled design. Forty middle-aged men with MetS (age: 53·97 ± 2·85 years, BMI = 31·09 ± 1·04 kg/m2) were randomly assigned to four groups, AE (n 10), ketogenic diet (KD; n 10), AE combined with KD (AE + KD; n 10) or control (C; n 10). RBP4, FABP5, body composition (body mass, BMI and body fat), insulin resistance, insulin sensitivity and MetS factors were evaluated prior to and after the 12-week intervention. AE + KD significantly decreased the body fat percentage (P = 0·006), BMI (P = 0·001), Zmets (P = 0·017), RBP4 (P = 0·017) and the homeostasis model of insulin resistance (HOMA-IR) (P = 0·001) as compared with control group and marginally significantly decreased the Zmets as compared with exercise group (P = 0·086). KD significantly decreased RBP4 levels as compared with control group (P = 0·041). Only the AE intervention (P = 0·045) significantly decreased FABP5 levels. Combining intervention of carbohydrate restriction with AE compared with carbohydrate restriction and AE alone improved RBP4, HOMA-IR as well as different body composition and MetS factors in middle-aged men with MetS.

Popular Dietary Trends' Impact on Athletic Performance: A Critical Analysis Review

BACKGROUND

Nutrition fuels optimal performance for athletes. With increased research developments, numerous diets available, and publicity from professional athletes, a review of dietary patterns impact on athletic performance is warranted.

RESULTS

The Mediterranean diet is a low inflammatory diet linked to improved power and muscle endurance and body composition. Ketogenic diets are restrictive of carbohydrates and proteins. Though both show no decrements in weight loss, ketogenic diets, which is a more restrictive form of low-carbohydrate diets, can be more difficult to follow. High-protein and protein-paced versions of low-carbohydrate diets have also shown to benefit athletic performance. Plant-based diets have many variations. Vegans are at risk of micronutrient deficiencies and decreased leucine content, and therefore, decreased muscle protein synthesis. However, the literature has not shown decreases in performance compared to omnivores. Intermittent fasting has many different versions, which may not suit those with comorbidities or specific needs as well as lead to decreases in sprint speed and worsening time to exhaustion.

CONCLUSIONS

This paper critically evaluates the research on diets in relation to athletic performance and details some of the potential risks that should be monitored. No one diet is universally recommend for athletes; however, this article provides the information for athletes to analyze, in conjunction with medical professional counsel, their own diet and consider sustainable changes that can help achieve performance and body habitus goals.

Ketogenic diets, exercise performance, and training adaptations

PURPOSE OF REVIEW

The ketogenic diet has been proposed as a nutritional strategy in sports. This review was undertaken to provide an overview of the recent literature concerning the effects of ketogenic diet on exercise performance and training adaptations.

RECENT FINDINGS

Most recent literature on the ketogenic diet and exercise performance showed no beneficial effects, especially for trained individuals. During a period of intensified training, performance was clearly impaired during the ketogenic intervention, while a diet with high carbohydrates maintained physical performance. The main effect of the ketogenic diet resides in metabolic flexibility, inducing the metabolism to oxidize more fat for ATP resynthesis regardless of submaximal exercise intensities.

SUMMARY

The ketogenic diet is not a reasonable nutritional strategy, as it has no advantage over normal/high carbohydrate-based diets on physical performance and training adaptations even when used only in a specific training/nutritional periodization stage.

Association between ß-Hydroxybutyrate Plasma Concentrations after Hypocaloric Ketogenic Diets and Changes in Body Composition

BACKGROUND

Early studies show that ketogenic diets (KDs) lead to preferential loss of fat mass (FM), whereas preserving fat-free mass (FFM). Additionally, animal data support the anticatabolic effects of DL-3-hydroxybutyrate. From our knowledge, a potential association between ß-hydroxybutyrate (ßHB) plasma concentrations and changes in body composition has never been explored.

OBJECTIVES

The main aim of this analysis was to determine if ßHB plasma concentrations, following hypocaloric KDs, were associated with FM and FFM changes in men and women with obesity.

METHODS

Data from 199 individuals (BMI = 36.6 ± 4.3 kg/m2; age = 43.6 ± 9.8 y; 82 men) were collated from 3 weight loss studies employing common measures of body composition (air displacement plethysmography) and ßHB plasma concentration (ELISA). The association between ßHB and weight, FM and FFM loss (kg), and %FFM loss (%FFML) was investigated with Spearman correlation. Multivariable linear regression was used to determine if ßHB was a significant predictor of the changes in anthropometric variables, after adjusting for confounding factors.

RESULTS

ßHB was not associated with FFML (% or kg), but a weak positive association was seen with FM loss (r = 0.182, P = 0.01, n = 199) and a trend with weight loss (r = 0.128, P = 0.072, n = 199). ßHB was a significant predictor of both weight and FM loss (kg), after adjusting for age, sex, baseline BMI, and intervention study.

CONCLUSIONS

The magnitude of ketosis is not associated with FFM preservation. However, the higher the level of ketosis, the greater the weight and FM loss. Further studies are needed to confirm these findings and to explore the mechanisms involved. This trial was registered at clinicaltrials.gov identifier as NCT01834859, NCT04051190, NCT02944253.

Position statement on nutrition therapy for overweight and obesity: nutrition department of the Brazilian association for the study of obesity and metabolic syndrome (ABESO-2022)

Obesity is a chronic disease resulting from multifactorial causes mainly related to lifestyle (sedentary lifestyle, inadequate eating habits) and to other conditions such as genetic, hereditary, psychological, cultural, and ethnic factors. The weight loss process is slow and complex, and involves lifestyle changes with an emphasis on nutritional therapy, physical activity practice, psychological interventions, and pharmacological or surgical treatment. Because the management of obesity is a long-term process, it is essential that the nutritional treatment contributes to the maintenance of the individual's global health. The main diet-related causes associated with excess weight are the high consumption of ultraprocessed foods, which are high in fats, sugars, and have high energy density; increased portion sizes; and low intake of fruits, vegetables, and grains. In addition, some situations negatively interfere with the weight loss process, such as fad diets that involve the belief in superfoods, the use of teas and phytotherapics, or even the avoidance of certain food groups, as has currently been the case for foods that are sources of carbohydrates. Individuals with obesity are often exposed to fad diets and, on a recurring basis, adhere to proposals with promises of quick solutions, which are not supported by the scientific literature. The adoption of a dietary pattern combining foods such as grains, lean meats, low-fat dairy, fruits, and vegetables, associated with an energy deficit, is the nutritional treatment recommended by the main international guidelines. Moreover, an emphasis on behavioral aspects including motivational interviewing and the encouragement for the individual to develop skills will contribute to achieve and maintain a healthy weight. Therefore, this Position Statement was prepared based on the analysis of the main randomized controlled studies and meta-analyses that tested different nutrition interventions for weight loss. Topics in the frontier of knowledge such as gut microbiota, inflammation, and nutritional genomics, as well as the processes involved in weight regain, were included in this document. This Position Statement was prepared by the Nutrition Department of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO), with the collaboration of dietitians from research and clinical fields with an emphasis on strategies for weight loss.

Effects of ketogenic diet on health outcomes: an umbrella review of meta-analyses of randomized clinical trials

BACKGROUND

Systematic reviews and meta-analyses of randomized clinical trials (RCTs) have reported the benefits of ketogenic diets (KD) in various participants such as patients with epilepsy and adults with overweight or obesity. Nevertheless, there has been little synthesis of the strength and quality of this evidence in aggregate.

METHODS

To grade the evidence from published meta-analyses of RCTs that assessed the association of KD, ketogenic low-carbohydrate high-fat diet (K-LCHF), and very low-calorie KD (VLCKD) with health outcomes, PubMed, EMBASE, Epistemonikos, and Cochrane database of systematic reviews were searched up to February 15, 2023. Meta-analyses of RCTs of KD were included. Meta-analyses were re-performed using a random-effects model. The quality of evidence per association provided in meta-analyses was rated by the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) criteria as high, moderate, low, and very low.

RESULTS

We included 17 meta-analyses comprising 68 RCTs (median [interquartile range, IQR] sample size of 42 [20-104] participants and follow-up period of 13 [8-36] weeks) and 115 unique associations. There were 51 statistically significant associations (44%) of which four associations were supported by high-quality evidence (reduced triglyceride (n = 2), seizure frequency (n = 1) and increased low-density lipoprotein cholesterol (LDL-C) (n = 1)) and four associations supported by moderate-quality evidence (decrease in body weight, respiratory exchange ratio (RER), hemoglobin A1c, and increased total cholesterol). The remaining associations were supported by very low (26 associations) to low (17 associations) quality evidence. In overweight or obese adults, VLCKD was significantly associated with improvement in anthropometric and cardiometabolic outcomes without worsening muscle mass, LDL-C, and total cholesterol. K-LCHF was associated with reduced body weight and body fat percentage, but also reduced muscle mass in healthy participants.

CONCLUSIONS

This umbrella review found beneficial associations of KD supported by moderate to high-quality evidence on seizure and several cardiometabolic parameters. However, KD was associated with a clinically meaningful increase in LDL-C. Clinical trials with long-term follow-up are warranted to investigate whether the short-term effects of KD will translate to beneficial effects on clinical outcomes such as cardiovascular events and mortality.

Investigating the Link between Ketogenic Diet, NAFLD, Mitochondria, and Oxidative Stress: A Narrative Review

Together with the global rise in obesity and metabolic syndrome, the prevalence of individuals who suffer from nonalcoholic fatty liver disease (NAFLD) has risen dramatically. NAFLD is currently the most common chronic liver disease and includes a continuum of liver disorders from initial fat accumulation to nonalcoholic steatohepatitis (NASH), considered the more severe forms, which can evolve in, cirrhosis, and hepatocellular carcinoma. Common features of NAFLD includes altered lipid metabolism mainly linked to mitochondrial dysfunction, which, as a vicious cycle, aggravates oxidative stress and promotes inflammation and, as a consequence, the progressive death of hepatocytes and the severe form of NAFLD. A ketogenic diet (KD), i.e., a diet very low in carbohydrates (<30 g/die) that induces "physiological ketosis", has been demonstrated to alleviate oxidative stress and restore mitochondrial function. Based on this, the aim of the present review is to analyze the body of evidence regarding the potential therapeutic role of KD in NAFLD, focusing on the interplay between mitochondria and the liver, the effects of ketosis on oxidative stress pathways, and the impact of KD on liver and mitochondrial function.

Effect of ketogenic diet on exercise tolerance and transcriptome of gastrocnemius in mice

Ketogenic diet (KD) has been proven to be an optional avenue in weight control. However, the impacts of KD on muscle strength and exercise endurance remain unclear. In this study, mice were randomly allocated to normal diet and KD groups to assess their exercise tolerance and transcriptomic changes of the gastrocnemius. KD suppressed body-weight and glucose levels and augmented blood ketone levels of mice. The total cholesterol, free fatty acids, and β-hydroxybutyric acid levels were higher and triglycerides and aspartate aminotransferase levels were lower in KD group. There was no notable difference in running distance/time and weight-bearing swimming time between the two groups. Furthermore, KD alleviated the protein levels of PGC-1α, p62, TnI FS, p-AMPKα, and p-Smad3, while advancing the LC3 II and TnI SS protein levels in the gastrocnemius tissues. RNA-sequencing found that 387 differentially expressed genes were filtered, and Cpt1b, Acadl, Eci2, Mlycd, Pdk4, Ptprc, C1qa, Emr1, Fcgr3, and Ctss were considered to be the hub genes. Our findings suggest that KD effectively reduced body weight but did not affect skeletal muscle strength and exercise endurance via AMPK/PGC-1α, Smad3, and p62/LC3 signaling pathways and these hub genes could be potential targets for muscle function in KD-treated mice.

The Ketogenic Diet and Neuroinflammation: The Action of Beta-Hydroxybutyrate in a Microglial Cell Line

The ketogenic diet (KD), a diet high in fat and protein but low in carbohydrates, is gaining much interest due to its positive effects, especially in neurodegenerative diseases. Beta-hydroxybutyrate (BHB), the major ketone body produced during the carbohydrate deprivation that occurs in KD, is assumed to have neuroprotective effects, although the molecular mechanisms responsible for these effects are still unclear. Microglial cell activation plays a key role in the development of neurodegenerative diseases, resulting in the production of several proinflammatory secondary metabolites. The following study aimed to investigate the mechanisms by which BHB determines the activation processes of BV2 microglial cells, such as polarization, cell migration and expression of pro- and anti-inflammatory cytokines, in the absence or in the presence of lipopolysaccharide (LPS) as a proinflammatory stimulus. The results showed that BHB has a neuroprotective effect in BV2 cells, inducing both microglial polarization towards an M2 anti-inflammatory phenotype and reducing migratory capacity following LPS stimulation. Furthermore, BHB significantly reduced expression levels of the proinflammatory cytokine IL-17 and increased levels of the anti-inflammatory cytokine IL-10. From this study, it can be concluded that BHB, and consequently the KD, has a fundamental role in neuroprotection and prevention in neurodegenerative diseases, presenting new therapeutic targets.

Nutritional Quality of Gluten-Free Bakery Products Labeled Ketogenic and/or Low-Carb Sold in the Global Market

Gluten-free and ketogenic bakery products are gaining momentum. This study aims to develop a better understanding of the nutritional quality of gluten-free bakery products labeled ketogenic and/or low-carb. For this reason, the products available on the global market that were labeled ketogenic and/or low-carb (n = 757) were retrieved and compared to standard gluten-free products (n = 509). Overall, nutritionally, no significant differences were found among ketogenic and/or low-carb products due the high intra-variability of each type, but they differed from standard products. Compared to standard products, all ketogenic and/or low carb, irrespective of categories, showed lower carbohydrates that derived chiefly from fibers and, to a lesser extent, from sugars. They also had higher protein contents (p < 0.05) compared to standard products. Fats was higher (p < 0.05) in ketogenic and/or low-carb baking mixes, savory biscuits, and sweet biscuits than in their standard counterparts. Saturated fats were higher (p < 0.05) in low-carb savory biscuits and breads, as well as in ketogenic sweet biscuits than in the same standard products. Overall, median values of the nutrients align with the definition of the ketogenic diet. Nevertheless, several products did not align with any of the ketogenic definitions. Therefore, consumers need to carefully read the nutritional facts and not rely on mentions such as low-cab and ketogenic to make their decision of purchase/consumption.

Low-Carbohydrate High-Fat Diet: A SWOC Analysis

Insulin resistance (IR) plays a role in the pathogenesis of many diseases, such as type 2 diabetes mellitus, cardiovascular disease, non-alcoholic fatty liver disease, obesity, and neurodegenerative diseases, including Alzheimer's disease. The ketogenic diet (KD) is a low-carbohydrate/high-fat diet that arose in the 1920s as an effective treatment for seizure control. Since then, the KD has been studied as a therapeutic approach for various IR-related disorders with successful results. To date, the use of the KD is still debatable regarding its safety. Some studies have acknowledged its usefulness, while others do not recommend its long-term implementation. In this review, we applied a SWOC (Strengths, Weaknesses, Opportunities, and Challenges) analysis that revealed the positive, constructive strengths of the KD, its potential complications, different conditions that can make used for it, and the challenges faced by both physicians and subjects throughout a KD. This SWOC analysis showed that the KD works on the pathophysiological mechanism of IR-related disorders such as chronic inflammation, oxidative stress and mitochondrial stress. Furthermore, the implementation of the KD as a potential adjuvant therapy for many diseases, including cancer, neurodegenerative disorders, polycystic ovary syndrome, and pain management was proven. On the other hand, the short and long-term possible undesirable KD-related effects, including nutritional deficiencies, growth retardation and nephrolithiasis, should be considered and strictly monitored. Conclusively, this review provides a context for decision-makers, physicians, researchers, and the general population to focus on this dietary intervention in preventing and treating diseases. Moreover, it draws the attention of scientists and physicians towards the opportunities and challenges associated with the KD that requires attention before KD initiation.

The Effects of Concurrent Training Combined with Low-Carbohydrate High-Fat Ketogenic Diet on Body Composition and Aerobic Performance: A Systematic Review and Meta-Analysis

(1) Background: Recently, studies have emerged to explore the effects of concurrent training (CT) with a low-carb, high-fat ketogenic diet (LCHF) on body composition and aerobic performance and observed its benefits. However, a large variance in the study design and observations is presented, which needs to be comprehensively assessed. We here thus completed a systematic review and meta-analysis to characterize the effects of the intervention combining CT and LCHF on body composition and aerobic capacity in people with training experience as compared to that combining CT and other dietary strategies. (2) Methods: A search strategy based on the PICOS principle was used to find literature in the databases of PubMed, Web of Science, EBSCO, Sport-discuss, and Medline. The quality and risk of bias in the studies were independently assessed by two researchers. (3) Result: Eight studies consisting of 170 participants were included in this work. The pooled results showed no significant effects of CT with LCHF on lean mass (SMD = -0.08, 95% CI -0.44 to 0.3, p = 0.69), body fat percentage (SMD = -0.29, 95% CI -0.66 to 0.08, p = 0.13), body mass (SMD = -0.21, 95% CI -0.53 to 0.11, p = 0.2), VO2max (SMD = -0.01, 95% CI -0.4 to 0.37, p = 0.95), and time (or distance) to complete the aerobic tests (SMD = -0.02, 95% CI -0.41 to 0.37, p = 0.1). Subgroup analyses also showed that the training background of participants (i.e., recreationally trained participants or professionally trained participants) and intervention duration (e.g., > or ≤six weeks) did not significantly affect the results. (4) Conclusions: This systematic review and meta-analysis provide evidence that compared to other dietary strategies, using LCHF with CT cannot induce greater benefits for lean mass, body fat percentage, body mass, VO2max, and aerobic performance in trained participants.

Very Low-Calorie Ketogenic Diet: A Potential Application in the Treatment of Hypercortisolism Comorbidities

A very low-calorie ketogenic diet (VLCKD) is characterized by low daily caloric intake (less than 800 kcal/day), low carbohydrate intake (<50 g/day) and normoproteic (1−1.5 g of protein/kg of ideal body weight) contents. It induces a significant weight loss and an improvement in lipid parameters, blood pressure, glycaemic indices and insulin sensitivity in patients with obesity and type 2 diabetes mellitus. Cushing’s syndrome (CS) is characterized by an endogenous or exogenous excess of glucocorticoids and shows many comorbidities including cardiovascular disease, obesity, type 2 diabetes mellitus and lipid disorders. The aim of this speculative review is to provide an overview on nutrition in hypercortisolism and analyse the potential use of a VLCKD for the treatment of CS comorbidities, analysing the molecular mechanisms of ketogenesis.