Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials

Keto therapy-unveiling the potential of ketogenic diet in psychiatric care: A scoping review

BACKGROUND

Within the framework of gut-brain interactions, the ketogenic diet (KD), a high-fat, low-carbohydrate, and moderate-protein dietary intervention, has gained attention for its potential in psychiatric care. Renowned for its efficacy in managing obesity, KD has demonstrated effectiveness in facilitating weight loss and inducing favorable metabolic changes in the short term. With its established benefits in neurological disorders, KD is now being investigated as a potential therapeutic avenue for individuals with psychiatric conditions.

OBJECTIVE

This scoping review aims to summarize the latest studies on this topic, consider clinical implications, and suggest future research directions.

METHODS

Records were systematically (PRISMA-ScR guidelines) identified through PubMed, Scopus, and EBSCOhost searches.

RESULTS

A total of 58 studies were initially identified, with 13 meeting the eligibility criteria. While clinical trials remain limited, emerging evidence from case reports, case series, and pilot studies highlights the potential of a KD in reducing symptoms across psychiatric conditions, including mood disorders, psychotic disorders, alcohol use, and eating disorders. A KD shows potential in reducing cravings in eating and alcohol use disorders by stabilizing brain metabolism and modulating addictive behaviors, while its neuroprotective and anti-inflammatory effects may contribute to symptom improvement in mood and psychotic disorders.

CONCLUSIONS

Implementing a KD in patients with mental disorders seems to be a feasible and well-tolerated approach, resulting in psychiatric symptom reduction and improvements in metabolic health. Most interestingly, research suggests that KD can also be safely implemented in the care of patients with addictive-like eating disorders.

Low carbohydrate high fat-diet in real life; A descriptive analysis of cardiovascular risk factors

Aims

Low Carbohydrate High Fat (LCHF) diets are popular for weight loss or glucose control. The main source of energy in such diets is fat but the composition of nutrients varies This study aims to investigate dietary variations in a real-world LCHF population and its associations with cardiovascular risk factors.

Methods

We recruited 100 volunteers who considered themselves adherent to a LCHF diet. Their last 14 days of dietary intake was assessed using diet history interviews. Validation of energy intake against expenditure was made using activity monitors. Predictive variables for the linear regression models were selected using stepwise bidirectional assessment of Akaike information criterion (AIC).

Results

Energy intake (E%) from carbohydrates was low, 8.7 E%, and fat was the main replacement. Dietary cholesterol was associated with higher total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL). Dietary sodium intake was associated with higher blood pressure. Protein intake was associated with lower diastolic blood pressure but also with lower HDL. The intake of dietary fibre was associated with lower LDL and total cholesterol but with higher hemoglobin A1c (HbA1c). The intake of carbohydrates and saturated fatty acids (SFA) was not associated with any of the outcome variables.

Conclusion

In this LCHF population, variations in intake of carbohydrates and saturated fatty acids could not predict any aspects of the cardiovascular risk profile. Lower fibre intake and higher cholesterol and sodium intake predicted a less favorable cardiovascular risk profile.

Hypocaloric low-carbohydrate versus low-fat diets on flow-mediated dilation, blood pressure, cardiovascular biomarkers, and body composition in individuals with overweight or obesity: a systematic review and meta-analysis of randomized clinical trials

Obesity can impair cardiometabolism, but low-carbohydrate diets (LCDs) may be beneficial for mitigating risk. We aimed to investigate the effects of LCDs versus low-fat diets (LFDs), under hypocaloric conditions, on flow-mediated dilation (FMD) in individuals with overweight/obesity. Secondarily, we assessed other cardiovascular markers (systolic blood pressure, diastolic blood pressure, C-reactive protein [CRP], high-density lipoprotein [HDL], low-density lipoprotein [LDL], triglycerides [TG], total cholesterol [TC]), and anthropometric and body composition measurements. PubMed, Scopus, and Web of Science were searched through May 2023 for studies involving hypocaloric LCDs versus LFDs on FMD. Meta-analyses were conducted for LCDs vs. LFDs to calculate weighted mean differences (WMD), including 10 studies reporting FMD (n = 475). Overall, hypocaloric LCDs resulted in a non-significant decrease in FMD compared with hypocaloric LFDs [WMD = -1.04% (95% CI -2.28 to 0.20), p = 0.10], while very-low-carbohydrate diets (VLCDs) significantly reduced FMD when compared with LFDs [WMD = -2.12% (95% CI: -3.35 to -0.9) p = 0.001]. LCDs did not change anthropometric and body composition measurements, nor CRP, blood pressure, HDL, or TC when compared with LFDs. However, LCDs significantly decreased TG [WMD = -19.94 mg/dL (95% CI -31.83 to -8.06), p = 0.001] and increased LDL [WMD = 20.00 mg/dL (95% CI 14.09 to 25.90), p = 0.001] when compared with LFDs. In conclusion, LCDs did not exert superior effects on cardiovascular markers or body composition when compared with LFDs in individuals with overweight or obesity, but LCDs reduced TG and increased LDL levels more than LFDs. Yet, vascular function (FMD) was reduced primarily for VLCDs.

Wash-in and washout effects: mitigating bias in short term dietary and other trials

Short term trials with surrogate measures instead of hard outcomes are often used to study chronic diseases. The effects of an intervention may, however, take time to develop and persist after discontinuation, producing wash-in and washout effects that threaten trial validity. This problem, especially involving carryover effects in crossover trials, is well recognized in the pharmacology and statistics literature but commonly disregarded in some areas of non-pharmaceutical research. Dietary trials, including feeding studies, are highly susceptible to bias because physiological adaptation to a major change in nutrients may take several weeks or longer. This article describes the nature and extent of this bias in nutrition research, as an important and illustrative case; considers implications for various other interventions; and proposes measures to strengthen causal inference.

Ketogenic Diet Intervention for Obesity Weight-Loss- A Narrative Review, Challenges, and Open Questions

PURPOSE OF REVIEW

The ketogenic diet (KD) has gained clinical attention for its potential benefits in weight loss and metabolic syndrome. By mimicking fasting through carbohydrate (CHO) restriction, KD shifts energy utilization to ketone bodies (KB) instead of glucose. Despite promising results, the effects on different weight loss indicators remain controversial, with challenges in monitoring adherence standards, optimal macronutrient composition, potential risks, and long-term sustainability. This article aims to review the different weight-loss outcomes of KD interventions for obesity, monitored by KB (adherence indication).

RECENT FINDINGS

Current literature on KD interventions for obesity weight loss monitored by KB show reduction in different outcomes, including body weight, body mass index, waist circumference, visceral adipose tissue, fat mass, and body fat percentage. Minor decreases in lean body mass and skeletal muscle mass were noted without resistance training. Variability existed in adherence (KB markers), CHO intake (7-27% of daily energy), diet duration (28 days to 12 months), and follow-up frequency (weekly to biannual). KD, particularly accompanied by exercise, positively influenced appetite regulation. KD interventions improves weight-related outcomes in participants with obesity but presents challenges in lean body mass reduction without resistance training and adherence variability. Standardizing methodologies, refining interventions and suitability to sub-populations, setting KB markers, and defining clinical relevance are essential for optimizing KD effectiveness.

Lipid Profiles After Changes in Alcohol Consumption Among Adults Undergoing Annual Checkups

Importance

Despite growing criticism of alcohol consumption due to its overall health risks, it remains unknown how changes in alcohol consumption, particularly cessation, affect lipid profiles outside of intense interventions.

Objective

To clarify the association of alcohol initiation and cessation with subsequent changes in low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C).

Design, Setting, and Participants

This cohort study included individuals undergoing annual checkups at a center for preventive medicine in Tokyo, Japan, from October 2012 to October 2022. Individuals treated with lipid-lowering medications were excluded. Data were analyzed from May to December 2024.

Exposures

Alcohol initiation (vs remaining abstainer) and cessation (vs continuing same alcohol intake) between 2 consecutive visits. One standard drink was equivalent to 10 g of pure ethanol.

Main Outcomes and Measures

Change in LDL-C and HDL-C levels between 2 consecutive visits.

Results

Among the 328 676 visits from 57 691 individuals (mean [SD] age, 46.8 [12.5] years; 30 576 female [53.0%]), the cohort for evaluating alcohol cessation comprised 49 898 visits among 25 144 participants (mean [SD] age, 49 [12.1] years; 12 334 female [49.1%]; mean [SD] LDL-C, 114.7 [28.4] mg/dL; mean [SD] HDL-C, 65.5 [16.4] mg/dL). Alcohol cessation was associated with changes in LDL-C of 1.10 mg/dL (95% CI, 0.76 to 1.45 mg/dL) among those discontinuing habits of fewer than 1.5 drinks/d, 3.71 mg/dL (95% CI, 2.71 to 4.71 mg/dL) for 1.5 to 3.0 drinks/d, and 6.53 mg/dL (95% CI, 5.14 to 7.91 mg/dL) for 3.0 or more drinks/d. Cessation was associated with a change in HDL-C of -1.25 mg/dL (95% CI, -1.41 to -1.09 mg/dL) among those discontinuing habits of fewer than 1.5 drinks/d, -3.35 mg/dL (-4.41 to -2.29 mg/dL) for 1.5 to 3.0 drinks/d, and -5.65 mg/dL (95% CI, -6.28 to -5.01 mg/dL) for 3.0 or more drinks/d. The cohort for evaluating alcohol initiation (107 880 visits; 29 042 participants) showed inverse dose-response associations.

Conclusions and Relevance

In this cohort study of Japanese annual health checkup participants, alcohol initiation was associated with modest cholesterol improvement, whereas cessation was associated with less favorable changes. After alcohol reduction, lipid profile changes should be carefully monitored to optimize cardiovascular disease risk management at both individual and population levels.

Reduced Serum PD-L1 and Markers of Inflammation in Response to Alternate Day Fasting With a Low-Carbohydrate Intervention: A Secondary Analysis of a Single-Arm Trial

This secondary analysis aimed to examine the effect of a single-arm alternate day fasting intervention with a 30% low-carbohydrate diet on biomarkers of inflammation and immune activation in adults with obesity. A 12-week weight-loss period was followed by a 12-week weight maintenance period. Anthropometrics and blood samples were collected at baseline and weeks 12 and 24. Multiplex assay was used to measure serum biomarkers including programmed death ligand 1 (PD-L1), interleukin 8 (IL-8), IL-1 receptor antagonist (IL-1ra), chemokine ligand (CCL)2, CCL4, interferon gamma (IFnγ), IFNγ-induced protein 10 (IP-10), and cluster of differentiation 40 ligand (CD40-L). In 28 participants, body weight and fat mass decreased during the weight-loss period but stabilized during the weight maintenance period. Serum PD-L1 decreased from baseline to week 12 (P = 0.005) but not at week 24. Moreover, IL-1ra and CCL4 concentrations decreased from baseline to week 24 (P < 0.001 and P < 0.008, respectively). Changes were not significant for in CCL2, IL-8, CD40-L, IFNγ, or IP-10. In conclusion, alternate day fasting-low carbohydrate modulates circulating immune biomarkers, which may be relevant to diabetes, cancer, and autoimmunity. This trial was registered at clinicaltrials.gov as NCT03528317 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6934424/).

Effects of Single Low-Carbohydrate, High-Fat Meal Consumption on Postprandial Lipemia and Markers of Endothelial Dysfunction: A Systematic Review of Current Evidence

CONTEXT

Postprandial lipemia (PPL) is associated with increased risk of endothelial dysfunction (ED), a precursor of atherosclerotic cardiovascular disease (ASCVD). The effects of low-carbohydrate, high-fat (LCHF) diets on ASCVD risk are uncertain; therefore, gaining a greater understanding of LCHF meals on PPL may provide valuable insights.

OBJECTIVE

The current systematic review investigated the effects of single LCHF meal consumption on PPL and markers of ED.

DATA SOURCES

CINAHL Plus, PubMed, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for key terms related to endothelial function, cardiovascular disease, glycemia, lipemia, and the postprandial state with no restriction on date.

DATA EXTRACTION

Full-text articles were independently screened by 2 reviewers, of which 16 studies were eligible to be included in the current review. All trials reported a minimum analysis of postprandial triglycerides (PPTG) following consumption of an LCHF meal (<26% of energy as carbohydrate). Results were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

DATA ANALYSIS

Single-meal macronutrient composition was found to play a key role in determining postprandial lipid and lipoprotein responses up to 8 hours post-meal. Consumption of LCHF meals increased PPTG and may contribute to ED via reduced flow-mediated dilation and increased oxidative stress; however, energy and macronutrient composition varied considerably between studies.

CONCLUSION

Consumption of an LCHF meal had a negative impact on PPL based on some, but not all, single-meal studies; therefore, the contribution of LCHF meals to cardiometabolic health outcomes remains unclear. Further research is needed on specific categories of LCHF diets to establish a causal relationship between postprandial modulation of lipids/lipoproteins and impaired vascular endothelial function.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD 42023398774.

The Influence of Dietary Patterns on Polycystic Ovary Syndrome Management in Women: A Review of Randomized Controlled Trials with and Without an Isocaloric Dietary Design

Polycystic ovary syndrome (PCOS) is an endocrine disorder that causes cardiometabolic and reproductive disorders in women of reproductive age. Women with PCOS are more likely to have obesity, type 2 diabetes mellitus, and cardiovascular disease. There is an inconclusive consensus on which dietary modification could be most effective in PCOS prevention and treatment. This review aimed to examine the effects of diverse dietary patterns on PCOS in women according to randomized controlled trials (RCTs) with and without an isocaloric dietary design. A literature search was performed in the PubMed®®/MEDLINE®® database up to 14 November 2024. A total of 21 RCTs were reviewed after screening the records, including 15 RCTs with a calorie-restricted dietary design and 6 RCTs with a non-calorie-restricted dietary design. This review found beneficial effects of the calorie-restricted Dietary Approaches to Stop Hypertension (DASH) diet on weight loss and glucose control in women with PCOS in four RCTs with an isocaloric dietary design. The calorie-restricted low-glycemic index (GI) diets from three RCTs and high-protein diets from four RCTs with an isocaloric dietary design showed no significant differences in anthropometric parameters, glucose control, lipids, and gonadal parameters compared with the control diet in women with PCOS. Non-calorie-restricted low-carbohydrate diets from four RCTs with an isocaloric dietary design showed similar results to the calorie-restricted low-GI diets and high-protein diets. However, the existing number of RCTs is insufficient to conclude the association between dietary patterns and PCOS in women. Further, well-designed dietary intervention studies are needed to assess the role of dietary patterns in PCOS beyond calorie restriction.

Feeding of a high protein, low carbohydrate diet leads to greater postprandial energy expenditure and fasted n6: n3 fatty acid ratio in lean, adult dogs compared to a moderate protein, moderate carbohydrate diet

High protein, low carbohydrate (HPLC) diets are often sought out by dog owners. They are reported to have beneficial effects on energy expenditure (EE), fat oxidation, and may alter the serum fatty acid profile. However, there is little to no data to support the feeding of HPLC diets to healthy adult dogs. Thus, the objective of the present study was to interrogate the health claims related to the feeding of HPLC diets to healthy adult dogs using a commercially available HPLC diet (48% of metabolizable energy (ME) from protein, 10% of ME from nitrogen-free extract; NFE), a moderate protein, moderate carbohydrate (MPMC) diet (28% of ME from protein, 39% of ME from NFE) formulated with the same ingredients as HPLC, and a commercially available, MPMC, high fiber, "metabolic" (MET) diet (30% of ME from protein, 37% of ME from NFE) as a commercial control. Diets were fed to 9 healthy, large breed dogs for 42 d in a Latin square design. Fasted blood samples were collected on days -2 (baseline), 12, 26 and 40, and indirect calorimetry was performed on 8 dogs on days 20 and 39 to measure respiratory quotient (RQ) and EE. Statistics were performed in SAS Studio (version 9.4). Dogs fed HPLC had a lower RQ at fasted (0.76), 0 to 4 h (0.78) and 5 to 10 h (0.83) post-meal compared to dogs fed MET (0.80, 0.83, 0.90) and MPMC (0.80, 0.84, 0.91; P < 0.05). All dogs had a similar EE at fasted but dogs fed HPLC had a greater postprandial EE at 0 to 4 h (5.36 kcal/kg0.75) and 5 to 10 h (5.46 kcal/kg0.75) compared to dogs fed MPMC (4.79 and 4.84 kcal/kg0.75; P < 0.05). Dogs fed MET (4.98, 4.96 kcal/kg0.75) were similar to both (P > 0.05). Alpha-linolenic acid (ALA; 18:3n3), docosapentaenoic acid (DPA; 22:5n3) and total n3 were all greater in dogs fed MET at each week (P < 0.05). In contrast, total n6: n3 and arachidonic acid (ARA; 20:4n6): eicosapentaenoic acid (EPA; 20:5n3) were both greater (P < 0.05) in dogs fed HPLC and MPMC compared to dogs fed MET at each week. This study represents the first to assess EE and serum fatty acids in adult large breed dogs consuming a HPLC diet for 6 wk. Consuming a HPLC diet led to potential beneficial effects of increased EE and fat oxidation after a meal, which has the potential to be useful in managing obesity, a common health concern in dogs.

Mixed methods evaluation of a low-carbohydrate high-fat nutrition education program for women from underserved communities in South Africa

South Africa faces a dual burden of non-communicable diseases (NCDs) and communicable diseases, exacerbated by the high consumption of processed foods. The Eat Better South Africa (EBSA) program implements community-based low-carbohydrate, high-fat (LCHF) interventions to address these issues. This study evaluated the impact of EBSA's 6-week program on the metabolic health and well-being of 32 women from underserved communities. It assessed outcomes before, immediately after, and six months post-intervention (n = 21). Quantitative findings showed significant improvements in key health markers. After six months, participants experienced an average weight loss of 5.6 kg (+- 5.5), a BMI reduction of 2 kg/m2, and a waist circumference decrease of 6.6 cm. Blood pressure dropped by 10.7 mmHg on average, and fasting glucose levels decreased significantly. Reductions were also observed in triglycerides and HbA1c, indicating better glycemic control. Liver function markers (GGT, ALT) and inflammation markers (CRP) improved as well. Qualitative analysis highlighted several key themes: participants were motivated by a desire to improve their health and lose weight but faced challenges such as social pressures, community violence, and scepticism about the diet's affordability and sustainability. Despite these barriers, positive experiences like increased energy and better hunger control were reported. Participants expressed the need for ongoing support to maintain these changes, both from the program and from their community. These findings suggest that LCHF diets can effectively manage metabolic conditions, but long-term adherence is challenged by socio-economic factors. The study highlights the importance of community-based interventions and highlights the need for further research to develop sustainable health strategies in low-income settings.

Development and Pragmatic Randomized Controlled Trial of Healthy Ketogenic Diet Versus Energy-Restricted Diet on Weight Loss in Adults with Obesity

Introduction: The ketogenic diet (KD) is widely used for weight management by reducing appetite, enhancing fat oxidation, and facilitating weight loss. However, the high content of total and saturated fats in a conventional KD may elevate low-density lipoprotein (LDL)-cholesterol levels, a known risk factor for cardiovascular diseases, highlighting the need for healthier alternatives. This study aimed to investigate the effect of a newly developed Healthy Ketogenic Diet (HKD) versus an Energy-Restricted Diet (ERD) on weight loss and metabolic outcomes among adults with obesity. Methods: Multi-ethnic Asian adults (n = 80) with body mass index ≥ 27.5 kg/m2 were randomized either to HKD (n = 41) or ERD (n = 39) for 6 months. Both groups followed an energy-restricted healthy diet, emphasizing on reducing saturated and trans fats. The HKD group additionally limited net carbohydrate intake to no more than 50 g per day. Dietary adherence was supported via the Nutritionist Buddy app with dietitian coaching. The primary outcome was weight change from baseline at 6 months. Secondary outcomes included weight change at 3 months and 1 year, along with changes in metabolic profiles. Data were analyzed using linear regression with an intention-to-treat approach. Results: The HKD group achieved significantly greater mean weight loss at 6 months than the ERD group (-7.8 ± 5.2 kg vs. -4.2 ± 5.6 kg, p = 0.01). The mean weight loss percentage at 6 months was 9.3 ± 5.9% and 4.9 ± 5.8% for the HKD and ERD groups, respectively (p = 0.004). Improvements in metabolic profiles were also significantly better in the HKD group [glycated hemoglobin (-0.3 ± 0.3% vs. -0.1 ± 0.2%, p = 0.008), systolic blood pressure (-7.7 ± 8.9 mmHg vs. -2.6 ± 12.2 mmHg, p = 0.005), and aspartate transaminase (-7.6 ± 15.5 IU/L vs. 0.6 ± 11.5 IU/L, p = 0.01)], with no increase in LDL-cholesterol (-0.12 ± 0.60 mmol/L vs. -0.04 ± 0.56 mmol/L, p = 0.97) observed in either group. Conclusions: The HKD was more effective than the ERD in promoting weight loss and improving cardiometabolic outcomes without elevation in LDL-cholesterol. It can be recommended for therapeutic intervention in patients with obesity.

The Cardioprotective Effects of Nutritional Ketosis: Mechanisms and Clinical Implications

Cardiovascular diseases (CVDs) persist as the primary cause of death worldwide, accounting for roughly 17.9 million fatalities each year. The prevalence of obesity, metabolic syndrome, and type 2 diabetes (key risk factors for CVD) continues to escalate at an alarming rate, necessitating novel therapeutic strategies to address this global health crisis. Nutritional ketosis, induced through ketogenic diets, modified fasting, intermittent fasting, and medium-chain triglyceride (MCT) oil consumption, has garnered attention for its potential cardioprotective effects. Ketosis is a metabolic state in which the body, due to a significantly reduced intake of carbohydrates, shifts its primary energy source from glucose to ketone bodies, i.e., beta-hydroxybutyrate (BHB), acetoacetate, and acetone, which are produced in the liver from fatty acids. This review examines the mechanisms by which ketone bodies, particularly BHB, mitigate cardiovascular risk. We focus mainly on the anti-inflammatory and antioxidative properties of BHB and summarize recent evidence to highlight the clinical relevance of ketosis in cardiometabolic health.

Exploring Biases of the Healthy Eating Index and Alternative Healthy Eating Index When Scoring Low-Carbohydrate and Low-Fat Diets

BACKGROUND

The Healthy Eating Index 2010 (HEI-2010) and Alternative Healthy Eating Index 2010 (AHEI-2010) are commonly used to measure dietary quality in research settings. Neither index is designed specifically to compare diet quality between low-carbohydrate (LC) and low-fat (LF) diets. It is unknown whether biases exist in making these comparisons.

OBJECTIVE

The aim was to determine whether HEI-2010 and AHEI-2010 contain biases when scoring LC and LF diets.

DESIGN

Secondary analyses of the Diet Intervention Examining the Factors Interacting With Treatment Success (DIETFITS) weight loss trial were conducted. The trial was conducted in the San Francisco Bay Area of California between January 2013 and May 2016. Three approaches were used to investigate whether biases existed for HEI-2010 and AHEI-2010 when scoring LC and LF diets.

PARTICIPANTS/SETTING

DIETFITS participants were assigned to follow healthy LC or healthy LF diets for 12 months (n = 609).

MAIN OUTCOMES MEASURES

Mean diet quality index scores for each diet were measured.

STATISTICAL ANALYSIS

Approach 1 examined both diet quality indices' scoring criteria. Approach 2 compared scores garnered by exemplary quality LC and LF menus created by registered dietitian nutritionists. Approach 3 used 2-sided t tests to compare the HEI-2010 and AHEI-2010 scores calculated from 24-hour dietary recalls of DIETFITS trial participants (n = 608).

RESULTS

Scoring criteria for both HEI-2010 (100 possible points) and AHEI-2010 (110 possible points) were estimated to favor an LF diet by 10 points. Mean scores for exemplary quality LF menus were higher than for LC menus using both HEI-2010 (91.8 vs 76.8) and AHEI-2010 (71.7 vs 64.4, adjusted to 100 possible points). DIETFITS participants assigned to a healthy LF diet scored significantly higher on HEI and AHEI than those assigned to a healthy LC diet at 3, 6, and 12 months (all, P < .001). Mean baseline scores were lower than mean scores at all follow-up time points regardless of diet assignment or diet quality index used.

CONCLUSIONS

Commonly used diet quality indices, HEI-2010 and AHEI-2010, showed biases toward LF vs LC diets. However, both indices detected expected changes in diet quality within each diet, with HEI-2010 yielding greater variation in scores. Findings support the use of these indices in measuring diet quality differences within, but not between, LC and LF diets.

Short-term high-fat and high-carb diet effects on glucose metabolism and hedonic regulation in young healthy men

Background

Daily dietary intake of macronutrients and energy is closely associated with long-term metabolic health outcomes, but whether 24-h nutritional intervention under isocaloric conditions leads to changes in metabolism remains unclear. Moreover, the short-term effect of diets with different macronutrient composition on hedonic appetite regulation is less clear.

Methods

This study examined the impact of an acute high-fat (F+) and high-carbohydrate (C+) diet on glucose metabolism and hedonic regulation of food intake in young healthy men under controlled conditions. Using a cross-over design, 19 male participants received a one-day isocaloric diet with different macronutrient composition (F+ = 11% carbohydrates, 74% fat; C+ = 79% carbohydrates, 6% fat) compared to a control diet (CON = 55% carbohydrates, 30% fat). Protein content was set at 15% of energy in all diets. The feeling of hunger, as well as "liking" and "wanting" for foods, was assessed through visual analog scales, and blood samples for glucose, insulin, and cortisol levels were assessed repeatedly during the experimental day. An intravenous glucose tolerance test was conducted the next morning.

Results

Postprandial glucose and insulin levels were lowest in F+ over the 24 h. Except for dinner, the CON diet showed the highest mean values in glucose. F+ diet improved insulin resistance, lowering Homeostatis Model Assessment Insulin Resistance (HOMA-IR) values. Changes in hedonic regulation of food intake were not observed during the intervention between the diets, except for higher feelings of satiety under the CON diet.

Conclusion

An acute, isocaloric, high-fat diet improved insulin resistance even in healthy individuals but did not affect hedonic food intake regulation. Macronutrient composition modulate glucose metabolism even under short-term (24-h) and isocaloric diets, which should be considered for personalized preventive dietary treatments.

The association between low carbohydrate dietary score (LCDS) and cardiovascular risk factors: results from the Shiraz Heart Study (SHS)

BACKGROUND

Cardiovascular disease (CVD) is a major cause of death and recent studies have highlighted the potential role of dietary carbohydrate indices in cardiovascular health. Given the controversial results in this field, the aim of this study was to investigate the association between low carbohydrate dietary score (LCDS) and CVD risk factors in a population of Iranian adults.

METHODS

This cross-sectional study was conducted within the framework of the Shiraz Heart Study (SHS) including 1982 adults. The validated 168 items food frequency questionnaire (FFQ) was used to assess participants' dietary intakes. To investigate the association between LCDS and cardiometabolic risk factors, logistic regression, was conducted.

RESULTS

During 5 years of follow-up, a total of 1982 adults, with a mean age of 53.07 ± 8.38 years, were included to the analysis. The adjusted model based on known confounding factors (age, sex, smoking, physical activity, energy intake and body mass index) revealed a significant decrease in a body shape index (ABSI) (OR = 0.70, 95% CI= (0.50 to 0.98), P = 0.038) comparing highest LCDS tertile vs. the reference. In contrast, risk of hypertension (HTN), body mass index (BMI), waist-hip ratio (WHR), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), atherogenic index of plasma (AIP), and fasting blood sugar (FBS) were not significantly associated with LCDS.

CONCLUSION

Current findings suggest that adherence to a low carbohydrate diet reduces ABSI, a main indicator of central obesity.

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.

Ketogenic Diet: A Review of Composition Diversity, Mechanism of Action and Clinical Application

The ketogenic diet (KD) is a special high-fat, very low-carbohydrate diet with the amount of protein adjusted to one's requirements. By lowering the supply of carbohydrates, this diet induces a considerable change in metabolism (of protein and fat) and increases the production of ketone bodies. The purpose of this article is to review the diversity of composition, mechanism of action, clinical application and risk associated with the KD. In the last decade, more and more results of the diet's effects on obesity, diabetes and neurological disorders, among other examples have appeared. The beneficial effects of the KD on neurological diseases are related to the reconstruction of myelin sheaths of neurons, reduction of neuron inflammation, decreased production of reactive oxygen species, support of dopamine production, repair of damaged mitochondria and formation of new ones. Minimizing the intake of carbohydrates results in the reduced absorption of simple sugars, thereby decreasing blood glucose levels and fluctuations of glycaemia in diabetes. Studies on obesity indicate an advantage of the KD over other diets in terms of weight loss. This may be due to the upregulation of the biological activity of appetite-controlling hormones, or to decreased lipogenesis, intensified lipolysis and increased metabolic costs of gluconeogenesis. However, it is important to be aware of the side effects of the KD. These include disorders of the digestive system as well as headaches, irritability, fatigue, the occurrence of vitamin and mineral deficiencies and worsened lipid profile. Further studies aimed to determine long-term effects of the KD are required.

Patients' experiences of dietary changes during a structured dietary intervention for irritable bowel syndrome

BACKGROUND

Diet plays an important role in management of gastrointestinal (GI) symptoms in patients with irritable bowel syndrome (IBS). Restrictive diets have gained popularity as treatment for IBS, but no studies have examined the patients' experiences of implementing such diets. Thus, the present study aimed to explore the experience of patients with IBS undergoing a structured dietary intervention.

METHODS

Using inductive content analysis, semi-structured interviews were conducted in 19 patients with IBS, who were recruited from a randomised controlled trial evaluating two different restrictive diets for 4 weeks: a diet low in total carbohydrates; and a diet low in fermentable oligo-, di- and monosaccharides and polyols (i.e., FODMAP) combined with traditional IBS dietary advice.

RESULTS

Three main themes developed from the qualitative analysis and together they describe the dietary intervention as supportive, as well as the dietary changes as challenging and contributing to reflection. Patients found the dietary support effective in both initiating and adhering to their dietary changes. Despite the support, the implementation of the diet was perceived as challenging when it interfered with other important aspects of their lives. However, going through the dietary change process, the patients began to reflect on their eating behaviours, which enabled individual dietary adjustments. The adjustments that patients maintained were not only a result of alleviation of GI symptoms, but also based on personal preferences.

CONCLUSIONS

Patients with IBS undergoing restrictive diets appear to benefit from structured support. However, considering the individual patient's life situation and personal preferences, individualised dietary options should be encouraged to achieve long-term dietary changes.

Therapeutic potential of the ketogenic diet: A metabolic switch with implications for neurological disorders, the gut-brain axis, and cardiovascular diseases

The Ketogenic Diet (KD) is a dietary regimen that is low in carbohydrates, high in fats, and contains adequate protein. It is designed to mimic the metabolic state of fasting. This diet triggers the production of ketone bodies through a process known as ketosis. The primary objective of KD is to induce and sustain ketosis, which has been associated with numerous health benefits. Recent research has uncovered promising therapeutic potential for KD in the treatment of various diseases. This includes evidence of its effectiveness as a dietary strategy for managing intractable epilepsy, a form of epilepsy that is resistant to medication. We are currently assessing the efficacy and safety of KD through laboratory and clinical studies. This review focuses on the anti-inflammatory properties of the KD and its potential benefits for neurological disorders and the gut-brain axis. We also explore the existing literature on the potential effects of KD on cardiac health. Our aim is to provide a comprehensive overview of the current knowledge in these areas. Given the encouraging preliminary evidence of its therapeutic effects and the growing understanding of its mechanisms of action, randomized controlled trials are warranted to further explore the rationale behind the clinical use of KD. These trials will ultimately enhance our understanding of how KD functions and its potential benefits for various health conditions. We hope that our research will contribute to the body of knowledge in this field and provide valuable insights for future studies.

A ketogenic diet, regardless of fish oil content, does not affect glucose homeostasis or muscle insulin response in male rats

Ketogenic diets (KDs) are very high in fat and low in carbohydrates. Evidence supports that KDs improve glucose metabolism in humans and rodents that are obese and/or insulin resistant. Conversely, findings in healthy rodents suggest that KDs may impair glucose homeostasis. In addition, most experimental KDs are composed of saturated and monounsaturated fatty acids, with almost no omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA). Evidence supports a beneficial role for n-3 LCPUFA on glucose homeostasis in the context of a metabolic challenge. To our knowledge, no study has examined whether the inclusion of n-3 LCPUFA affects the impact of a KD on glucose homeostasis. The objective of this study was to examine the impact of a KD on whole body glucose tolerance and skeletal muscle insulin response in rats and to determine if increasing the n-3 LCPUFA content in a KD with menhaden oil could improve metabolic outcomes. Male Sprague-Dawley rats were pair-fed one of a low-fat diet, high-fat diet, KD, or a KD supplemented with menhaden oil for 8 wk. No significant differences in whole body glucose tolerance, skeletal muscle insulin signaling, or skeletal muscle insulin-stimulated glucose uptake were detected between the dietary groups. Our findings suggest that KD feeding, with or without supplementation of n-3 LCPUFA, does not affect whole body glucose homeostasis or skeletal muscle insulin response under pair-feeding conditions.NEW & NOTEWORTHY Ketogenic diets (KDs) improve glucose metabolism in humans and rodents that are insulin resistant, but their impact is unclear in a healthy context. Furthermore, standard KDs typically lack beneficial omega-3 long-chain polyunsaturated fatty acids (n3-LCPUFA). This study assessed whether supplementing a KD with n3-LCPUFA could alter glucose homeostasis or skeletal muscle insulin response. No differences were observed between a standard KD and a KD with n3-LCPUFA when energy intake was controlled.

The ketogenic diet does not improve cardiac function and blunts glucose oxidation in ischaemic heart failure

AIMS

Cardiac energy metabolism is perturbed in ischaemic heart failure and is characterized by a shift from mitochondrial oxidative metabolism to glycolysis. Notably, the failing heart relies more on ketones for energy than a healthy heart, an adaptive mechanism that improves the energy-starved status of the failing heart. However, whether this can be implemented therapeutically remains unknown. Therefore, our aim was to determine if increasing ketone delivery to the heart via a ketogenic diet can improve the outcomes of heart failure.

METHODS AND RESULTS

C57BL/6J male mice underwent either a sham surgery or permanent left anterior descending coronary artery ligation surgery to induce heart failure. After 2 weeks, mice were then treated with either a control diet or a ketogenic diet for 3 weeks. Transthoracic echocardiography was then carried out to assess in vivo cardiac function and structure. Finally, isolated working hearts from these mice were perfused with appropriately 3H or 14C labelled glucose (5 mM), palmitate (0.8 mM), and β-hydroxybutyrate (β-OHB) (0.6 mM) to assess mitochondrial oxidative metabolism and glycolysis. Mice with heart failure exhibited a 56% drop in ejection fraction, which was not improved with a ketogenic diet feeding. Interestingly, mice fed a ketogenic diet had marked decreases in cardiac glucose oxidation rates. Despite increasing blood ketone levels, cardiac ketone oxidation rates did not increase, probably due to a decreased expression of key ketone oxidation enzymes. Furthermore, in mice on the ketogenic diet, no increase in overall cardiac energy production was observed, and instead, there was a shift to an increased reliance on fatty acid oxidation as a source of cardiac energy production. This resulted in a decrease in cardiac efficiency in heart failure mice fed a ketogenic diet.

CONCLUSION

We conclude that the ketogenic diet does not improve heart function in failing hearts, due to ketogenic diet-induced excessive fatty acid oxidation in the ischaemic heart and a decrease in insulin-stimulated glucose oxidation.

Sex-dependent associations of serum BDNF, glycolipid metabolism and cognitive impairments in Parkinson's disease with depression: a comprehensive analysis

Brain-derived neurotrophic factor (BDNF) and glycolipid metabolism have been implicated in cognitive impairments and depression among Parkinson's disease (PD). However, the role of sex differences in this relationship remains elusive. This study aimed to investigate the potential sex differences in the link between serum BDNF levels, glycolipid metabolism and cognitive performance among depressive PD patients. PD patients comprising 108 individuals with depression and 108 without depression were recruited for this study. Cognitive function was assessed using the Montreal Cognitive Assessment Beijing version (MOCA-BJ). The severity of depressive symptoms was assessed using the Hamilton Depression Rating Scale (HAMD-17), while motor symptoms were evaluated using the Revised Hoehn and Yahr rating scale (H-Y) and the Unified Parkinson's Disease Rating Scale Part III (UPDRS-III). Laboratory testing and enzyme-linked immunosorbent assay (ELISA) are used to measure serum levels of glycolipid metabolism and BDNF. Females showed superior performance in delayed recall (all p < 0.05), male PD patients exhibited higher scores in naming tasks compared to females in non-depression group. There was no sex differences in serum BDNF levels between depression and non-depression groups. Liner regression analysis indicated BDNF as an independent risk factor for language deficits in male PD patients with depression (p < 0.05), while cholesterol (CHOL) emerged as a cognitive influencing factor, particularly in delayed recall among male PD patients with depression (p < 0.05). Our study reveals extensive cognitive impairments in PD patients with depression. Moreover, BDNF and CHOL may contribute to the pathological mechanisms underlying cognitive deficits, particularly in male patients with depression.

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.

Low-Carbohydrate Diet is More Helpful for Weight Loss Than Low-Fat Diet in Adolescents with Overweight and Obesity: A Systematic Review and Meta-Analysis

Purpose

This manuscript performed a meta-analysis to compare the effects of a low-fat diet (LFD) and a low-carbohydrate diet (LCD) on body weight and lipid levels in adolescents with overweight and obesity.

Patients and Methods

PubMed and other databases were searched for the full-text literature comparing LFD and LCD up to November 2023 using a subject plus free word strategy, with search terms such as "low-fat diet", "low-carbohydrate diet", "obesity", "weight", "adolescents", "RCT", and so on. Two independent reviewers selected promising candidate trials, collected the data, and assessed the quality of the trials. RevMan 5.3 software was utilized to conduct a meta-analysis of the randomized controlled trials (RCTs) that were included.

Results

5 RCTs with 192 participants were included in this meta-analysis. Weight (mean difference -2.81; 95% CI -5.38 to -0.25), Body Mass Index (BMI) (-1.13; 95% CI -2.14 to -0.11) and Triglyceride (TG) (-0.36; 95% CI -0.46 to -0.27) of the LCD were significantly lower than that of the LFD. At the same time, the high-density lipoprotein cholesterol (HDL) levels of the LCD were significantly higher than those of the LFD (0.08; 95% CI 0.04 to 0.12) (P < 0.05). However, there was no significant difference in the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), percent body fat, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL) between the two groups (P>0.05).

Conclusion

According to this study, LCD is more helpful in improving weight loss, HDL and TG. Thus, LCD may serve as an effective intervention for weight management in adolescents with overweight and obesity, although further research is needed to determine its long-term effects.

The effect of a nurse-led low carbohydrate regimen on anthropometric and laboratory parameters of patients with metabolic syndrome: a quasi-experimental study

Introduction

Metabolic syndrome is a global health concern. It is a condition that includes a cluster of various risk factors for type 2 diabetes and cardiovascular disease. This quasi-experimental study investigates the effect of a nurse-led low-carbohydrate regimen on anthropometric and laboratory parameters in metabolic syndrome patients.

Methods

The study used a quasi-experimental design conducted at the University of Mosul; 128 participants meeting the metabolic syndrome criteria were recruited and divided into the intervention and control groups. The intervention group received personalized counseling and support in implementing a low-carb regime, while the control group received standard advice. The study participants were assessed by anthropometry, and laboratory parameters were evaluated pre- and post-intervention. Statistical data analysis was conducted using IBM-SPSS 27, including chi-square, Fisher's exact test, t-tests, and the Mcnemar test, which were performed to compare the changes within and between groups.

Results

The mean age of the participants in the intervention and control groups was 50.72 ± 6.43 years and 49.14 ± 6.89 years, respectively. Compared to the control group, the intervention group experienced a significant positive reduction in anthropometric measures and laboratory parameters, including weight, body mass index (BMI), waist circumference, lipid profiles, and HbA1c.

Conclusion

A tangible effect of nurse-led interventions based on low-carbohydrate regimens in managing metabolic syndrome was empirically authenticated. Positive changes were observed in the intervention group regarding anthropometric measures and laboratory parameters. However, future research may require a larger sample size and a longer follow-up to confirm these effects and evaluate long-term metabolic impacts.

A pilot study of Keto Prescribed+: A healthy thinking and eating educational program for African American women

ABSTRACT

African American (AA) women have the highest prevalence of obesity in addition to health disparities in preventable diet-related diseases (i.e., diabetes, hypertension), which places them at increased risk for cardiovascular disease. The purpose of this pilot study was to assess the feasibility, acceptability, and preliminary effectiveness of the Keto Prescribed+ (KetoRx+) program on associated physical and psychosocial outcomes among this population. The KetoRx+ program is a healthy eating and thinking educational intervention. The program combined online and in-person community group sessions over 8 weeks. The Keto Prescribed+ was found to be feasible and acceptable with comments on ways to increase acceptability from participants completing program (n = 10). Physical outcomes changed showed an average decrease in weight of 10lbs (SD = 5), baseline average 226lbs. Waist-to-hip ratio and systolic blood pressure also trended down. Psychosocial outcomes showed improvement trends. The KetoRx+ program is feasible and acceptable for overweight or obese AA women. Preliminary efficacy was established for most physical and psychosocial outcomes. However, more research is needed to identify specific program components contributing to healthy lifestyle behavior change and to establish program efficacy and effectiveness. Culturally adapted community-based biopsychosocial interventions using ketogenic nutrition therapy may help improve cardiovascular health of adult AA women.

Improved Gut Health May Be a Potential Therapeutic Approach for Managing Prediabetes: A Literature Review

Given the growing global threat and rising prevalence of type 2 diabetes mellitus (T2DM), addressing this metabolic disease is imperative. T2DM is preceded by prediabetes (PD), an intermediate hyperglycaemia that goes unnoticed for years in patients. Several studies have shown that gut microbial diversity and glucose homeostasis in PD or T2DM patients are affected. Therefore, this review aims to synthesize the existing literature to elucidate the association between high-calorie diets, intestinal permeability and their correlation with PD or T2DM. Moreover, it discusses the beneficial effects of different dietary interventions on improving gut health and glucose metabolism. The primary factor contributing to complications seen in PD or T2DM patients is the chronic consumption of high-calorie diets, which alters the gut microbial composition and increases the translocation of toxic substances from the intestinal lumen into the bloodstream. This causes an increase in inflammatory response that further impairs glucose regulation. Several dietary approaches or interventions have been implemented. However, only a few are currently in use and have shown promising results in improving beneficial microbiomes and glucose metabolism. Therefore, additional well-designed studies are still necessary to thoroughly investigate whether improving gut health using other types of dietary interventions can potentially manage or reverse PD, thereby preventing the onset of T2DM.

Association of low carbohydrate diet score with the risk of type 2 diabetes in an Australian population: A longitudinal study

AIMS

We aimed to assess the association of a low carbohydrate diet score (LCD) with the incidence of type 2 diabetes (T2D) using Melbourne Collaborative Cohort Study (MCCS) data.

METHODS

Between 1990 and 1994, the MCCS recruited 41,513 people aged 40-69 years. The first and second follow-ups were conducted in 1995-1998 and 2003-2007, respectively. We analyzed data from 39,185 participants. LCD score was calculated at baseline as the percentage of energy from carbohydrate, fat, and protein. The higher the score the less percentage of carbohydrates contributed to energy intake. The association of LCD quintiles with the incidence of diabetes was assessed using modified Poisson regression, adjusted for lifestyle, obesity, socioeconomic and other confounders. Mediation of the association by adiposity (BMI) was assessed.

RESULTS

LCD was positively associated with diabetes risk. Higher LCD score (p for trend = 0.001) was associated with increased risk of T2D. Quintile 5 (38 % energy from carbohydrates) versus quintile 1 (55 % energy from carbohydrates) showed a 20 % increased diabetes risk (incidence risk ratio (IRR) = 1.20 (95 % CI: 1.05-1.37)). A further adjustment for BMI (Body Mass Index) and WHR (Waist-to-Hip-Ratio) eliminated the association. Mediation analysis demonstrated that BMI mediated 76 % of the LCD & diabetes association.

CONCLUSIONS

Consuming a low carbohydrate diet, reflected as a high LCD score, may increase the risk of T2D which is largely explained by obesity. Results highlight the need for further studies, including clinical trials investigating the effects of a low carbohydrate diet in T2D.

Associations of Lower-Carbohydrate and Lower-Fat Diets with Mortality among People with Cardiovascular Disease

BACKGROUND

Although low-carbohydrate and low-fat diets have been shown to have short-term metabolic benefits, the associations of these dietary patterns, particularly different food sources and macronutrient quality, with mortality in people with cardiovascular disease (CVD) remain unclear.

OBJECTIVES

To examine the associations of different types of lower-carbohydrate diets (LCDs) and lower-fat diets (LFDs) with mortality in individuals with CVD.

METHODS

This study included 3971 adults with CVD from the NHANES 1999-2014. Mortality status was linked to National Death Index mortality data through 31 December 2019. Overall, unhealthy and healthy LCD and LFD scores were determined based on the percentages of energy from total and subtypes of carbohydrate, fat, and protein. Cox proportional hazards regression models were applied to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Higher healthy LCD score was associated with favorable blood lipids and higher homeostasis model assessment of insulin resistance, whereas higher unhealthy LFD score was associated with lower high-density lipoprotein and higher C-reactive protein at baseline (all P-trend < 0.05). During 35,150 person-years of follow-up, 2163 deaths occurred. For per 20-percentile increment in dietary scores, the multivariate-adjusted HRs of all-cause mortality were 0.91 (95% CI: 0.86, 0.96) for healthy LCD score (P < 0.001), 0.94 (95% CI: 0.89, 1.00) for healthy LFD score (P = 0.04), and 1.07 (95% CI: 1.00, 1.14) for unhealthy LFD score (P = 0.04).

CONCLUSIONS

Overall LCD and LFD scores are not associated with total mortality. Unhealthy LFD scores are associated with higher total mortality, whereas healthy LCD and LFD scores are associated with lower mortality in people with CVD.

Low-carbohydrate diet for people with type 2 diabetes mellitus

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the effects of a low-carbohydrate diet in adults with type 2 diabetes mellitus.

Should carbohydrate-modified diets be the first option for weight loss in people with impaired glucose metabolism? A scoping review

While the "precision nutrition" movement is at an early stage of development, several investigations have compared low-fat versus carbohydrate (CHO)-modified diets (i.e., low-or-reduced-CHO, low glycemic index/load diets, and high-fiber) in people with normal versus impaired glucose metabolism. The purpose of this scoping review was to summarize evidence in support of the hypothesis that CHO-modified diets are more effective for weight loss among people with impaired glucose metabolism. Fifteen articles were included in this review: seven retrospective analyses of randomized clinical trials and eight prospective randomized clinical trials with prespecified hypotheses related to a diet (low-fat vs. CHO-modified) × phenotype (normal vs. impaired) interaction. Evidence in support of the hypothesis was identified in six of seven retrospective and three of eight prospective studies, which led to a recommendation of CHO-modified diets as a first-line option for people with impaired glucose metabolism. However, the evidence in support of this recommendation is relatively weak, and dietary prescriptions should consider additional contextual information that may influence overall dietary adherence. Additional and rigorous research using innovative randomized experimental approaches is needed for stronger dietary weight loss recommendations based on pretreatment glycemic status.

Low-carbohydrate dietary score and the incidence of metabolically unhealthy phenotype based on BMI status: a cohort study

There is scarce research focusing on the relationship between the low-carbohydrate dietary score and the development of a metabolically unhealthy phenotype. Therefore, this cohort study was designed to assess the association between the low-carbohydrate dietary score and the risk of metabolically unhealthy phenotypes (MUP). This study included 1299 adults with healthy metabolic profiles who were followed for 5.9 years. Results indicated an inverse association between the second tertile of the low-carbohydrate dietary score and the risk of developing metabolically unhealthy obesity (MUO) (HR: 0.76, 95% CI: 0.59-0.98). In addition, we found an inverse association between the healthy low-carbohydrate dietary score and the risk of MUO (HR: 0.77, 95% CI: 0.60-0.99). Our results revealed a nonlinear inverse association between the low-carbohydrate dietary score and the risk of MUP only in subjects with overweight or obesity. This relationship was independent of animal protein and fat intake. Also, we found that a lower intake of unhealthy carbohydrates was associated with a lower risk of MUP only in subjects with overweight or obesity.

Diet and Meal Pattern Determinants of Glucose Levels and Variability in Adults with and without Prediabetes or Early-Onset Type 2 Diabetes: A Pilot Study

This observational pilot study examined the association between diet, meal pattern and glucose over a 2-week period under free-living conditions in 26 adults with dysglycemia (D-GLYC) and 14 with normoglycemia (N-GLYC). We hypothesized that a prolonged eating window and late eating occasions (EOs), along with a higher dietary carbohydrate intake, would result in higher glucose levels and glucose variability (GV). General linear models were run with meal timing with time-stamped photographs in real time, and diet composition by dietary recalls, and their variability (SD), as predictors and glucose variables (mean glucose, mean amplitude of glucose excursions [MAGE], largest amplitude of glucose excursions [LAGE] and GV) as dependent variables. After adjusting for calories and nutrients, a later eating midpoint predicted a lower GV (β = -2.3, SE = 1.0, p = 0.03) in D-GLYC, while a later last EO predicted a higher GV (β = 1.5, SE = 0.6, p = 0.04) in N-GLYC. A higher carbohydrate intake predicted a higher MAGE (β = 0.9, SE = 0.4, p = 0.02) and GV (β = 0.4, SE = 0.2, p = 0.04) in N-GLYC, but not D-GLYC. In summary, our data suggest that meal patterns interact with dietary composition and should be evaluated as potential modifiable determinants of glucose in adults with and without dysglycemia. Future research should evaluate causality with controlled diets.

Increased low-density lipoprotein cholesterol on a low-carbohydrate diet in adults with normal but not high body weight: A meta-analysis

BACKGROUND

Low-density lipoprotein (LDL) cholesterol change with consumption of a low-carbohydrate diet (LCD) is highly variable. Identifying the source of this heterogeneity could guide clinical decision-making.

OBJECTIVES

To evaluate LDL cholesterol change in randomized controlled trials involving LCDs, with a focus on body mass index (BMI) in kg/m2.

METHODS

Three electronic indexes (Pubmed, EBSCO, and Scielo) were searched for studies between 1 January, 2003 and 20 December, 2022. Two independent reviewers identified randomized controlled trials involving adults consuming <130 g/d carbohydrate and reporting BMI and LDL cholesterol change or equivalent data. Two investigators extracted relevant data, which were validated by other investigators. Data were analyzed using a random-effects model and contrasted with results of pooled individual participant data.

RESULTS

Forty-one trials with 1379 participants and a mean intervention duration of 19.4 wk were included. In a meta-regression accounting for 51.4% of the observed variability on LCDs, mean baseline BMI had a strong inverse association with LDL cholesterol change [β = -2.5 mg/dL/BMI unit, 95% confidence interval (CI): -3.7, -1.4], whereas saturated fat amount was not significantly associated with LDL cholesterol change. For trials with mean baseline BMI <25, LDL cholesterol increased by 41 mg/dL (95% CI: 19.6, 63.3) on the LCD. By contrast, for trials with a mean of BMI 25-<35, LDL cholesterol did not change, and for trials with a mean BMI ≥35, LDL cholesterol decreased by 7 mg/dL (95% CI: -12.1, -1.3). Using individual participant data, the relationship between BMI and LDL cholesterol change was not observed on higher-carbohydrate diets.

CONCLUSIONS

A substantial increase in LDL cholesterol is likely for individuals with low but not high BMI with consumption of an LCD, findings that may help guide individualized nutritional management of cardiovascular disease risk. As carbohydrate restriction tends to improve other lipid and nonlipid risk factors, the clinical significance of isolated LDL cholesterol elevation in this context warrants investigation. This trial was registered at PROSPERO as CRD42022299278.

Ketogenic diet and behavior: insights from experimental studies

As a journal page for full details. The ketogenic diet (KD) has been established as a treatment for epilepsy, but more recently it has been explored as an alternative or add-on therapy for many other diseases ranging from weight loss to neurological disorders. Animal models are widely used in studies investigating the therapeutic effects of the KD as well as underlying mechanisms. Especially in the context of neurological, psychiatric, and neurodevelopmental disorders essential endpoints are assessed by behavioral and motor tests. Here we summarized research evaluating the influence of the KD on cognition, depressive and anxiety-related behaviors, and social and nutritional behaviors of laboratory rodents. Each section contains a brief description of commonly used behavioral tests highlighting their limitations. Ninety original research articles, written in English, performed on mice or rats, providing measurement of blood beta-hydroxybutyrate (BHB) levels and behavioral evaluation were selected for the review. The majority of research performed in various disease models shows that the KD positively impacts cognition. Almost an equal number of studies report a reduction or no effect of the KD on depressive-related behaviors. For anxiety-related behaviors, the majority of studies show no effect. Despite the increasing use of the KD in weight loss and its appetite-reducing properties the behavioral evaluation of appetite regulation has not been addressed in preclinical studies. This review provides an overview of the behavioral effects of nutritional ketosis addressed to a broad audience of scientists interested in the KD field but not necessarily specializing in behavioral tests.

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

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

The effect of traditional diet on glucose homoeostasis in carriers and non-carriers of a common TBC1D4 variant in Greenlandic Inuit: a randomised crossover study

Consumption of traditional foods is decreasing amid a lifestyle transition in Greenland as incidence of type 2 diabetes (T2D) increases. In homozygous carriers of a TBC1D4 variant, conferring postprandial insulin resistance, the risk of T2D is markedly higher. We investigated the effects of traditional marine diets on glucose homoeostasis and cardio-metabolic health in Greenlandic Inuit carriers and non-carriers of the variant in a randomised crossover study consisting of two 4-week dietary interventions: Traditional (marine-based, low-carbohydrate) and Western (high in imported meats and carbohydrates). Oral glucose tolerance test (OGTT, 2-h), 14-d continuous glucose and cardio-metabolic markers were assessed to investigate the effect of diet and genotype. Compared with the Western diet, the Traditional diet reduced mean and maximum daily blood glucose by 0·17 mmol/l (95 % CI 0·05, 0·29; P = 0·006) and 0·26 mmol/l (95 % CI 0·06, 0·46; P = 0·010), respectively, with dose-dependency. Furthermore, it gave rise to a weight loss of 0·5 kg (95 % CI; 0·09, 0·90; P = 0·016) relative to the Western diet and 4 % (95 % CI 1, 9; P = 0·018) lower LDL:HDL-cholesterol, which after adjustment for weight loss appeared to be driven by HDL elevation (0·09 mmol/l (0·03, 0·15), P = 0·006). A diet-gene interaction was indicated on insulin sensitivity in the OGTT (p = 0·093), which reflected a non-significant increase of 1·4 (-0·6, 3·5) mmol/l in carrier 2-h glucose. A Traditional diet marginally improved daily glycaemic control and plasma lipid profile compared with a Westernised diet in Greenlandic Inuit. Possible adverse effects on glucose tolerance in carriers of the TBC1D4 variant warrant further studies.

Effect of carbohydrate restriction on body weight in overweight and obese adults: a systematic review and dose-response meta-analysis of 110 randomized controlled trials

Introduction

Carbohydrate-restricted diets are one of the most effective dietary interventions for weight loss. However, the optimum carbohydrate intake for implementing the most effective weight-loss interventions is still being discussed. We aimed to determine the optimum carbohydrate intake for short- and long-term weight loss in adults with overweight and obesity.

Methods

We searched PubMed, Scopus, Web of Science, and CENTRAL from inception to May 2021 for randomized controlled trials examining the effect of a carbohydrate-restricted diet (≤45% of energy intake) as compared to a control diet (carbohydrate intake >45% of energy intake) on body weight in adults with overweight/obesity. A random-effects dose-response meta-analysis was conducted to calculate the mean difference for each 10% decrease in carbohydrate intake at the 6-month follow-up (1 to 6 months), 12-month follow-up (6 to 12 months), and follow-up longer than 12 months. The shape of the dose-dependent effects was also evaluated. The certainty of the evidence was rated using the GRADE approach. The minimal clinically important difference (MCID) threshold was defined as 5% weight loss (equal to 4.39 kg).

Results

A total of 110 trials were selected for the present meta-analysis. In the linear dose-response meta-analysis, each 10% decrease in carbohydrate intake reduced body weight by 0.64 kg (95% CI: -0.79 to -0.49; n = 101 trials with 4,135 participants, high-certainty evidence) at the 6-month follow-up and by 1.15 kg (95% CI: -1.61 to -0.69; 42 trials with 2,657 participants, moderate-certainty evidence) at the 12-month follow-up. Non-linear dose-response meta-analyses indicated a monotonic reduction in body weight with the decrease in carbohydrate intake, with the greatest reduction at 5% at the 6-month follow-up (mean difference 5%: -3.96 kg, 95% CI: -4.92 to -3.00) and 10% at the 12-month follow-up (mean difference 10%: -6.26 kg, 95% CI: -10.42 to -2.10). At follow-up longer than 12 months, dose-response analyses suggested a non-linear effect, wherein carbohydrate intakes higher than 40% and lower than 30% were not effective for weight loss.

Discussion

Carbohydrate restriction is an effective dietary strategy for important weight loss in adults with overweight and obesity. At 6-month and 12-month follow-ups, body weight decreased proportionally, more than the MCID threshold, along with the decrease in carbohydrate intake. At follow-up longer than 12 months, there was a non-linear effect, with the greatest reduction at 30% carbohydrate intake.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022315042.

Optimization of nutritional strategies using a mechanistic computational model in prediabetes: Application to the J-DOIT1 study data

Lifestyle interventions have been shown to prevent or delay the onset of diabetes; however, inter-individual variability in responses to such interventions makes lifestyle recommendations challenging. We analyzed the Japan Diabetes Outcome Intervention Trial-1 (J-DOIT1) study data using a previously published mechanistic simulation model of type 2 diabetes onset and progression to understand the causes of inter-individual variability and to optimize dietary intervention strategies at an individual level. J-DOIT1, a large-scale lifestyle intervention study, involved 2607 subjects with a 4.2-year median follow-up period. We selected 112 individuals from the J-DOIT1 study and calibrated the mechanistic model to each participant's body weight and HbA1c time courses. We evaluated the relationship of physiological (e.g., insulin sensitivity) and lifestyle (e.g., dietary intake) parameters with variability in outcome. Finally, we used simulation analyses to predict individually optimized diets for weight reduction. The model predicted individual body weight and HbA1c time courses with a mean (±SD) prediction error of 1.0 kg (±1.2) and 0.14% (±0.18), respectively. Individuals with the most and least improved biomarkers showed no significant differences in model-estimated energy balance. A wide range of weight changes was observed for similar model-estimated caloric changes, indicating that caloric balance alone may not be a good predictor of body weight. The model suggests that a set of optimal diets exists to achieve a defined weight reduction, and this set of diets is unique to each individual. Our diabetes model can simulate changes in body weight and glycemic control as a result of lifestyle interventions. Moreover, this model could help dieticians and physicians to optimize personalized nutritional strategies according to their patients' goals.

A Review of Healthy Dietary Choices for Cardiovascular Disease: From Individual Nutrients and Foods to Dietary Patterns

Cardiovascular disease (CVD) remains the first cause of mortality globally. Diet plays a fundamental role in cardiovascular health and is closely linked to the development of CVD. Numerous human studies have provided evidence on the relationship between diet and CVD. By discussing the available findings on the dietary components that potentially influence CVD progression and prevention, this review attempted to provide the current state of evidence on healthy dietary choices for CVD. We focus on the effects of individual macronutrients, whole food products, and dietary patterns on the risks of CVD, and the data from population-based trials, observational studies, and meta-analyses are summarized. Unhealthy dietary habits, such as high intake of saturated fatty acids, sugar-sweetened beverages, red meat, and processed meat as well as high salt intake are associated with the increased risk of CVD. Conversely, increased consumption of plant-based components such as dietary fiber, nuts, fruits, and vegetables is shown to be effective in reducing CVD risk factors. The Mediterranean diet appears to be one of the most evidence-based dietary patterns beneficial for CVD prevention. However, there is still great debate regarding whether the supplementation of vitamins and minerals confers cardioprotective benefits. This review provides new insights into the role of dietary factors that are harmful or protective in CVD, which can be adopted for improved cardiovascular health.

Targeting microbiota in dietary obesity management: a systematic review on randomized control trials in adults

Obesity is an alarming public health problem. Tailored nutritional therapy is advisable since emerging evidence on complex cross-talks among multifactorial agents. In this picture, the gut microbiota is highly individualized and intricately dependent on dietary patterns, with implications for obesity management. Most of the papers on the topic are observational and often conflicting. This review aimed to systematically organize the body of evidence on microbiota deriving from dietary trials in adult obesity giving the most certain phylogenetic, and metabolomic signatures in relation to both the host metabolism and phenotype changes published until now. We retrieved 18 randomized control trials on 1385 subjects with obesity who underwent several dietary interventions, including standard diet and healthy dietary regimens. Some phyla and species were more related to diets rich in fibers and others to healthy diets. Weight loss, metabolism improvements, inflammatory markers decrease were specifically related to different microorganisms or functions. The Prevotella/Bacteroides ratio was one of the most reported predictors. People with the burden of obesity comorbidities had the most significant taxonomic changes in parallel with a general improvement. These data emphasize the possibility of using symbiotic approaches involving tailored diets, microbiota characteristics, and maybe drugs to treat obesity and metabolic disorders. We encourage Authors to search for specific phylogenetic associations beyond a too generally reported Firmicutes/Bacteroides ratio.

Carbohydrate-insulin model: does the conventional view of obesity reverse cause and effect?

Conventional obesity treatment, based on the First Law of Thermodynamics, assumes that excess body fat gain is driven by overeating, and that all calories are metabolically alike in this regard. Hence, to lose weight one must ultimately eat less and move more. However, this prescription rarely succeeds over the long term, in part because calorie restriction elicits predictable biological responses that oppose ongoing weight loss. The carbohydrate-insulin model posits the opposite causal direction: overeating doesn't drive body fat increase; instead, the process of storing excess fat drives overeating. A diet high in rapidly digestible carbohydrates raises the insulin-to-glucagon ratio, shifting energy partitioning towards storage in adipose, leaving fewer calories for metabolically active and fuel sensing tissues. Consequently, hunger increases, and metabolic rate slows in the body's attempt to conserve energy. A small shift in substrate partitioning though this mechanism could account for the slow but progressive weight gain characteristic of common forms of obesity. From this perspective, the conventional calorie-restricted, low-fat diet amounts to symptomatic treatment, failing to target the underlying predisposition towards excess fat deposition. A dietary strategy to lower insulin secretion may increase the effectiveness of long-term weight management and chronic disease prevention. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

Benefits of Chronic Administration of a Carbohydrate-Free Diet on Biochemical and Morphometric Parameters in a Rat Model of Diet-Induced Metabolic Syndrome

Carbohydrate intake restriction positively affects markers related to metabolic syndrome (MS). However, the effects of long-term carbohydrate-free diets (CFD) have yet to be studied. The main objective of this study was to report the effects on biochemical and morphometric parameters in a rat model of MS. Male Wistar rats were initially divided into two groups: the standard diet group (SD, n = 20); and the MS group (n = 30) fed a high-glucose diet. Ten animals from each group were sacrificed after 20 weeks on their respective diets to verify MS development. The remaining MS animals were divided into two subgroups: one continued with the MS diet (n = 10); and the other transitioned to a carbohydrate-free diet (MS + CFD group, n = 10) for 20 more weeks. At week 40, parameters, including glucose, insulin, lipid profile, ketone bodies, C-reactive protein (CRP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, creatinine, liver and muscle glycogen, and serum, hepatic, renal, and pancreatic malondialdehyde (MDA) levels were assessed. Transitioning to CFD resulted in decreased caloric intake and body weight, with normalized parameters including MDA, insulin, lipid profile, ALT, liver glycogen, creatinine, and CRP levels. This shift effectively reversed the MS-induced alterations, except for glycemia and uremia, likely influenced by the diet's high protein content stimulating gluconeogenesis. This research underscores the potential benefits of long-term carbohydrate restriction in mitigating MS-related markers.

Effects of very low-carbohydrate ketogenic diets on lipid profiles in normal-weight (body mass index < 25 kg/m2) adults: a meta-analysis

CONTEXT

Very low-carbohydrate diets or ketogenic diets (KDs) have garnered attention for weight loss in patients with overweight or obesity as well as for normal-weight adults, yet the adverse effects of KDs, such as dyslipidemia in normal-weight adults, have not been studied extensively.

OBJECTIVE

This meta-analysis aimed to identify the effects of KDs on the lipid profile in normal-weight (body mass index [BMI] < 25 kg/m2) adults from randomized controlled trials.

DATA SOURCES

PubMed and Embase databases were searched on November 21, 2021, using search terms representing KDs and lipid profiles. Two researchers independently screened articles according to PICOS inclusion criteria.

DATA EXTRACTION

General study information, dietary data, and lipid profiles were extracted from eligible studies. Risk of bias was assessed using the Cochrane risk of bias 2 tool.

DATA ANALYSIS

Fixed- or random-effects meta-analysis was performed to estimate the effects of KDs on total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides, apolipoprotein A (apoA), and apolipoprotein B (apoB), considering heterogeneity across studies. The certainty of evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach.

RESULTS

Three studies were selected for meta-analysis. A KD significantly increased TC by 1.47 mmol/L (95%CI, 0.72-2.22 mmol/L), LDL-C by 1.08 mmol/L (95%CI, 0.37-1.79 mmol/L), and apoB by 0.35 g/L (95%CI, 0.06-0.65 g/L). In addition, a KD significantly increased HDL-C by 0.35 mmol/L (95%CI, 0.27-0.42 mmol/L) and apoA by 0.34 g/L (95%CI, 0.28-0.41 g/L) compared with control diets. Triglyceride levels were not significantly different between KDs and control diets (P = 0.63).

CONCLUSION

This study suggests unfavorable effects of KDs on TC and LDL-C in normal-weight adults. Although an increase in HDL-C can compensate for unfavorable changes in lipids, normal-weight individuals should consider the risk of hypercholesterolemia when consuming a KD. Results for triglycerides were inconsistent.

Short- and long-term effects of very low- and low-calorie ketogenic diets on metabolism and cardiometabolic risk factors: a narrative review

Worldwide obesity and cardiovascular diseases have encouraged the adoption of new and efficient dietary strategies. Among various proposed diets, ketogenic diets, both the very-low-calorie ketogenic diet (VLCKD) and the low-calorie ketogenic diet (LCKD), have been suggested in recent years as an effective nutritional approach for obesity management. The VLCKD and the LCKD are characterized by a low carbohydrate content (<50 g/day), 1-1.5 g of protein/kg of ideal body weight, less than 20-30 g of lipids, and a daily intake of about 800 calories for VLCKD and about 1200-1400 calories for LCKD. The purpose of our narrative review is to offer an overview of the most impactful studies in the scientific literature regarding VLCKD and LCKD to discuss their short- and long-term effects (less than 12 months and more than 12 months respectively) on weight loss, metabolic and cardiovascular aspects. Articles we focused on were cohort studies, case-control studies, cross-sectional studies, randomized controlled trials, and meta-analyses. Results indicate that VLCKD and LCKD could be helpful to ameliorate metabolic and cardiovascular risk factors such as weight loss, glucose, and cholesterol levels, both in the short and long term. Further research in this area may include more randomized controlled trials to gather more data.

Weight, insulin resistance, blood lipids, and diet quality changes associated with ketogenic and ultra low-fat dietary patterns: a secondary analysis of the DIETFITS randomized clinical trial

Background

The DIETFITS trial reported no significant difference in 12-month weight loss between a healthy low-fat and healthy low-carbohydrate diet. Participants were instructed to restrict fat or carbohydrates to levels consistent with a ketogenic or ultra low-fat diet for 2  months and to subsequently increase intakes until they achieved a comfortable maintenance level.

Objective

To compare 3- and 12-month changes in body weight and cardiometabolic risk factors between a subsample of participants who reported 3-month fat or carbohydrates intakes consistent with either a ketogenic-like diet (KLD) or ultra low-fat diet (ULF).

Design

3-month and 12-month weight and risk factor outcomes were compared between KLD (n = 18) and ULF (n = 21) sub-groups of DIETFITS participants (selected from n = 609, healthy overweight/obese, aged 18-50  years).

Results

Less than 10% of DIETFITS participants met KLD or ULF criteria at 3-months. Both groups achieved similar weight loss and insulin resistance improvements at 3-months and maintained them at 12- months. Significant differences at 3-months included a transient ~12% increase in LDL cholesterol (LDL-C) for KLD with a concomitant greater reduction in log(TG/HDL), a measure of LDL-C's atherogenic potential. The latter was maintained at 12-months, despite substantial diet recidivism for both groups, whereas LDL-C levels were similar for ULF at baseline and 12-months. KLD participants achieved and maintained the greatest reductions in added sugars and refined grains at 3- months and 12-months, whereas ULF participants reported a 50% increase in refined grains intake from baseline to 12-months.

Conclusion

Among the ~10% of study participants that achieved the most extreme restriction of dietary fat vs. carbohydrate after 3  months, weight loss and improvement in insulin sensitivity were substantial and similar between groups. At 12  months, after considerable dietary recidivism, the few significant differences in diet quality and blood lipid parameters tended to favor KLD over ULF.