Clinical Evidence of Low-Carbohydrate Diets against Obesity and Diabetes Mellitus

The dual challenge of diabesity: pathophysiology, management, and future directions

Diabesity, the concurrent occurrence of obesity and type-2 diabetes mellitus (T2DM), represents a pressing global health challenge characterized by intricate pathophysiological mechanisms and a wide range of associated comorbidities. Central to its development are insulin resistance, metabolic syndrome, and chronic low-grade inflammation mediated by dysregulated adipokine secretion and systemic metabolic dysfunction. These mechanisms underpin the progression of diabesity and its complications, including cardiovascular disease and hypertension. Management strategies encompass lifestyle interventions focusing on tailored dietary modifications and structured physical activity, pharmacological treatments targeting both glycemic control and weight loss, and surgical interventions such as bariatric surgery, which have demonstrated efficacy in achieving durable outcomes. Clinical trials and meta-analyses underscore the comparative advantages of different treatment modalities in terms of efficacy, safety, and sustainability. Moreover, long-term follow-up studies emphasize the critical need for sustained multidisciplinary interventions to prevent relapse and enhance patient outcomes. Future advancements in management include exploring precision medicine approaches that integrate individual metabolic profiles, lifestyle factors, and emerging therapeutic innovations. A multidisciplinary approach combining advanced therapeutic strategies and patient-centered care remains pivotal for optimizing management and improving prognoses for individuals with diabesity. This review highlights the complex interplay between obesity and T2DM, offering comprehensive insights into their pathophysiology, clinical presentation, and management paradigms.

Efficacy of Low-Carbohydrate Diets Versus Low-Fat Diets in Glycemic Control Among Patients With Type 2 Diabetes: A Systematic Review

This systematic review evaluates the comparative efficacy of low-carbohydrate diets (LCDs) versus low-fat diets (LFDs) in improving glycemic control, weight management, and lipid profiles in individuals with type 2 diabetes mellitus (T2DM) or prediabetes. Seven randomized controlled trials involving diverse populations were included, with dietary interventions ranging from very low-carbohydrate ketogenic (LCK) diets (typically <10% of total caloric intake from carbohydrates, with higher fat and moderate protein) to moderate carbohydrate regimens (30-45% of total calories). LFDs, in contrast, prioritized carbohydrate intake (50-60% of total calories), with reduced fat (<20-30%) and moderate protein (15-20%). Across studies, LCDs consistently demonstrated greater reductions in HbA1c, fasting glucose, and triglycerides, alongside superior weight loss and increased high-density lipoprotein cholesterol compared to LFDs. Additionally, LCDs were associated with significant reductions in diabetes medication use, highlighting their potential to decrease pharmacological dependency and improve metabolic outcomes, including enhanced insulin sensitivity and reduced inflammation. Despite variability in long-term outcomes and adherence, LCDs emerged as a promising alternative to traditional dietary approaches for managing T2DM. Further research is warranted to explore strategies to improve dietary adherence, such as behavioral interventions and technological support, and to evaluate long-term sustainability, including their effects on cardiovascular health and quality of life. These findings underscore the transformative potential of LCDs in diabetes management and highlight the need for personalized dietary approaches.

Quantitative analysis of the caloric restriction versus isocaloric diets models based on macronutrients composition: impacts on body weight regulation, anthropometric, and bioimpedance parameters in women with obesity

Introduction

Obesity is a growing public health issue, especially among young adults, with long-term management strategies still under debate. This prospective study compares the effects of caloric restriction and isocaloric diets with different macronutrient distributions on body composition and anthropometric parameters in obese women during a 12-week weight loss program, aiming to identify the most effective dietary strategies for managing obesity-related health outcomes.

Methods

A certified clinical nutritionist assigned specific diets over a 12-week period to 150 participants, distributed as follows: hypocaloric diets-low-energy diet (LED, 31 subjects) and very low-energy diet (VLED, 13 subjects); isocaloric diets with macronutrient distribution-low-carbohydrate diet (LCD, 48 subjects), ketogenic diet (KD, 23 subjects), and high-protein diet (HPD, 24 subjects); and isocaloric diet without macronutrient distribution-time-restricted eating (TRE, 11 subjects). Participants were dynamically monitored using anthropometric parameters: body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and bioelectrical impedance analysis (BIA) using the TANITA Body Composition Analyzer BC-418 MA III (T5896, Tokyo, Japan) at three key intervals-baseline, 6 weeks, and 12 weeks. The following parameters were evaluated: body weight, basal metabolic rate (BMR), percentage of total body fat, trunk fat, muscle mass, fat-free mass, and hydration status.

Results

All diets led to weight loss, but differences emerged over time. The TRE model resulted in significantly less weight loss compared to LED at the final follow-up (6.30 kg, p < 0.001), similar to the VLED (4.69 kg, p < 0.001). Isocaloric diets with varied macronutrient distributions showed significant weight loss compared to LED (p < 0.001). The KD reduced waist circumference at both 6 and 12 weeks (-4.08 cm, p < 0.001), while significant differences in waist-to-hip ratio reduction were observed across diet groups at 12 weeks (p = 0.01). Post-hoc analysis revealed significant fat mass differences at 12 weeks, with HPD outperforming IF (p = 0.01) and VLED (p = 0.003). LCD reduced trunk fat at 6 weeks (-2.36%, p = 0.001) and 12 weeks (-3.79%, p < 0.001). HPD increased muscle mass at 12 weeks (2.95%, p = 0.001), while VLED decreased it (-2.02%, p = 0.031). TRE showed a smaller BMR reduction at 12 weeks compared to LED.

Conclusion

This study highlights the superior long-term benefits of isocaloric diets with macronutrients distribution over calorie-restrictive diets in optimizing weight, BMI, body composition, and central adiposity.

Effects of Specially Designed Energy-Restricted Diet on Anthropometric Parameters and Cardiometabolic Risk in Overweight and Obese Adults: Pilot Study

BACKGROUND/AIMS

This study examined the effects of a specially designed energy-restricted diet with alternate carbohydrate intake on body composition and cardiometabolic risk factors in overweight and obese adults. The aim was to assess whether the intervention could lead to significant weight loss, improve body composition, and reduce cardiometabolic risks.

METHODS

Sixty-five participants (34 women, 31 men) with an average BMI of 31.8 ± 9.1 kg/m2 (women) and 34.1 ± 6.4 kg/m2 (men) participated in a 14-week intervention. The diet included different days of carbohydrate intake and a 20% reduction in total daily energy consumption. Anthropometric measurements and biochemical parameters, including predictive indices of cardiometabolic risk, were determined at baseline and after the intervention.

RESULTS

The intervention resulted in a significant reduction in body weight (mean weight loss of 17%, p < 0.001), with 64.6% of participants achieving a weight loss of at least 10%. Muscle mass as a percentage of total body weight increased. Cardiometabolic improvements were observed in fasting blood glucose (from 5.4 to 4.9 mmol/L, p < 0.001) and LDL cholesterol (from 3.38 to 2.81 mmol/L, p < 0.001). Gender-specific differences were found, particularly in HDL-C, which decreased significantly in women (p = 0.013), while there was a non-significant increase in men. Cardiometabolic indices, including the Visceral Adiposity Index (VAI) and the Cardiometabolic Index (CMI), also improved significantly.

CONCLUSIONS

The alternate carbohydrate diet improved body composition, cardiometabolic health, and treatment adherence through metabolic flexibility. However, the short duration of this study and the lack of a control group suggest that further research is needed to assess long-term sustainability.

A protein-rich meal provides beneficial glycemic and hormonal responses as compared to meals enriched in carbohydrate, fat or fiber, in individuals with or without type-2 diabetes

Introduction

Diet stands as a pivotal modifiable risk factor influencing weight gain and the onset of type-2 diabetes (T2D). This study delves into the variation in glucose and regulatory pancreatic hormone levels subsequent to the consumption of meals with differing macronutrient compositions.

Methods

The cohort comprised 20 individuals diagnosed with T2D and 21 without diabetes. Participants underwent a cross-over design, consuming four isocaloric meals (600 kcal) enriched in carbohydrate, fiber, fat and protein. Plasma glucose, insulin and glucagon levels were measured at -30, and -5 min, followed by subsequent measurements every 30 min for 240 min post meal intake. Quantification of alterations in the postprandial state was accomplished through the incremental area under the curve (iAUC) and the incremental peak height for the insulin:glucagon ratio (IGR) and plasma glucose levels. The meal demonstrating the lowest responses across these variables was deemed the optimal meal.

Results

Meals rich in protein and fat, and consequently low in carbohydrate, exhibited reduced incremental peak and iAUC for both glucose and the IGR in comparison to the other meals. While the protein-enriched meal neared optimal standards, it proved less efficient for individuals without T2D and possessing a low BMI, as well as in those with T2D and poor glycemic control.

Conclusion

Our findings endorse the adoption of protein-enriched, low-carbohydrate meals to curtail the meal-induced anabolic hormonal response while averting excessive fluctuations in glucose levels.

Soy-Based High-Protein Spheric Foods with the Appearance of Familiar Sugary Snacks

Excessive consumption of sugary foods increases the likelihood of obesity, as well as the preventable risk of lifestyle illnesses such as diabetes and cardiovascular diseases. Frequent intake of sweet snacks is considered to increase the risk of overweight/obesity in industrial nations. However, we cannot stop snacking against our better judgment. Therefore, in this study, we sought to develop high-protein, low-carb "mock snacks" to satisfy snack lovers' appetites and nutrition. Soy protein-based, ball-shaped food products with 57.7% (w/w) protein and 3.6% sugar have been developed. The addition of canola oil made them melty in the mouth without sacrificing their crispiness. Moreover, evaluation of the surface topography of the "soy balls" by 3D laser scanning demonstrated their high degree of sphericity. Conclusively, the snacks developed here may be one of the healthy alternatives for the current sugary ones.

Mapping the landscape of research on insulin resistance: a visualization analysis of randomized clinical trials

BACKGROUND

Insulin resistance, a condition in which cells do not respond adequately to insulin, plays a crucial role in diabetes and related metabolic disorders. Randomized clinical trials (RCTs) explore interventions to manage insulin resistance, contributing to evidence-based medical progress. The current study aimed to analyze the global research landscape and trends in RCTs targeting insulin resistance.

METHODS

This study used bibliometric analysis and data visualization to examine RCT publications on insulin resistance from 2003 to 2022. The Scopus database was used due to its comprehensive coverage. The search strategy involved combining terms related to insulin resistance with RCT-related terms. The search query was validated, and core bibliometric indicators were used to analyze publication growth, origin, productivity, quality, and citations.

RESULTS

Between 2003 and 2022, 1077 RCT-focused publications on insulin resistance were identified from a pool of 24,932 related articles. The growth followed two phases, with a significant increase after 2008. The USA (n = 308; 28.60%), Iran (n = 165; 15.32%), China (n = 110; 10.21%), and the UK (n = 92; 8.54%) were the main contributors. The active institutions included Tehran University of Medical Sciences (n = 38; 3.53%) and Harvard Medical School (n = 31; 2.88%). Prominent funding agencies include the National Institutes of Health (n = 88; 8.17%) and the National Institute of Diabetes and Digestive and Kidney Diseases (n = 86; 7.99%). The top journals included the American Journal of Clinical Nutrition (n = 44; 4.09%) and Diabetes Care (n = 35; 3.25%). Co-occurrence analysis revealed three clusters addressing "utilizing lipid panels as indicators of insulin resistance," "analyzing the impact of diet composition and physical activity on insulin sensitivity among obese individuals," and "exploring insulin resistance in cases of polycystic ovary syndrome."

CONCLUSIONS

This comprehensive bibliometric analysis highlights the global research landscape and trends in RCTs targeting insulin resistance. Research on lipid panels, diet impact, and insulin resistance in patients with polycystic ovary syndrome will continue to be a hotspot. The findings offer valuable information on research priorities, international collaborations, and impactful publications. This study provides a foundation for future directorial investigations in this critical area of metabolic health.

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

BACKGROUND

Diabesity, the intersection of obesity and diabetes, presents a global health crisis with profound implications. Addressing diabesity requires multifaceted strategies, with diet playing a pivotal role. Over the last 15 years, clinical studies have intensified their exploration of various dietary approaches in diabesity management. This literature review aims to synthesize findings from clinical studies conducted in the last 15 years, shedding light on the efficacy, mechanisms, and nuances of different diet types in diabesity management with special focus on the Mediterranean diet (MD).

METHODS

Thorough research of academic databases yielded a collection of relevant clinical studies. These studies encompassed a range of dietary strategies, including the MD, low-carbohydrate diets, plant-based diets, high-protein diets, low-fat regimens, and intermittent fasting. Key findings, methodologies, and outcomes were thoroughly extracted and analyzed.

RESULTS

The last 15 years have witnessed considerable improvements in recognizing the role of human nutritional habits in diabesity management. The MD appears to be the most well-recognized diet, exerting favorable effects against both obesity and diabetes. Low-carbohydrate diets were found to enhance glycemic regulation and decrease insulin resistance. Plant-based diets demonstrated potential benefits in weight management and cardiometabolic health. High-protein, low-fat dietary models exhibited positive effects on satiety and body weight decline. Intermittent fasting regimens also exerted metabolic improvements and body weight decline. Personalization emerged as a crucial factor in dietary recommendations.

CONCLUSIONS

Clinical studies from the last 15 years underscore the intricate relationship between diet types and diabesity management. The above results contribute to an increasing body of evidence, emphasizing the need for tailored dietary approaches and especially the MD. Healthcare providers can utilize this knowledge to offer personalized dietary recommendations for individuals with diabesity, potentially curbing the rise of these twin epidemics and improving the well-being of affected populations.

The Relationship of Ketogenic Diet with Neurodegenerative and Psychiatric Diseases: A Scoping Review from Basic Research to Clinical Practice

BACKGROUND

The ketogenic diet (KD) has become widespread for the therapy of epileptic pathology in childhood and adulthood. In the last few decades, the current re-emergence of its popularity has focused on the treatment of obesity and diabetes mellitus. KD also exerts anti-inflammatory and neuroprotective properties, which could be utilized for the therapy of neurodegenerative and psychiatric disorders.

PURPOSE

This is a thorough, scoping review that aims to summarize and scrutinize the currently available basic research performed in in vitro and in vivo settings, as well as the clinical evidence of the potential beneficial effects of KD against neurodegenerative and psychiatric diseases. This review was conducted to systematically map the research performed in this area as well as identify gaps in knowledge.

METHODS

We thoroughly explored the most accurate scientific web databases, e.g., PubMed, Scopus, Web of Science, and Google Scholar, to obtain the most recent in vitro and in vivo data from animal studies as well as clinical human surveys from the last twenty years, applying effective and characteristic keywords.

RESULTS

Basic research has revealed multiple molecular mechanisms through which KD can exert neuroprotective effects, such as neuroinflammation inhibition, decreased reactive oxygen species (ROS) production, decreased amyloid plaque deposition and microglial activation, protection in dopaminergic neurons, tau hyper-phosphorylation suppression, stimulating mitochondrial biogenesis, enhancing gut microbial diversity, restoration of histone acetylation, and neuron repair promotion. On the other hand, clinical evidence remains scarce. Most existing clinical studies are modest, frequently uncontrolled, and merely assess the short-term impacts of KD. Moreover, several clinical studies had large dropout rates and a considerable lack of compliance assessment, as well as an increased level of heterogeneity in the study design and methodology.

CONCLUSIONS

KD can exert substantial neuroprotective effects via multiple molecular mechanisms in various neurodegenerative and psychiatric pathological states. Large, long-term, randomized, double-blind, controlled clinical trials with a prospective design are strongly recommended to delineate whether KD may attenuate or even treat neurodegenerative and psychiatric disease development, progression, and symptomatology.