The carbohydrate-insulin model of obesity posits that high-carbohydrate diets lead to excess insulin secretion, thereby promoting fat accumulation and increasing energy intake. Thus, low-carbohydrate ...diets are predicted to reduce ad libitum energy intake as compared to low-fat, high-carbohydrate diets. To test this hypothesis, 20 adults aged 29.9 ± 1.4 (mean ± s.e.m.) years with body mass index of 27.8 ± 1.3 kg m
were admitted as inpatients to the National Institutes of Health Clinical Center and randomized to consume ad libitum either a minimally processed, plant-based, low-fat diet (10.3% fat, 75.2% carbohydrate) with high glycemic load (85 g 1,000 kcal
) or a minimally processed, animal-based, ketogenic, low-carbohydrate diet (75.8% fat, 10.0% carbohydrate) with low glycemic load (6 g 1,000 kcal
) for 2 weeks followed immediately by the alternate diet for 2 weeks. One participant withdrew due to hypoglycemia during the low-carbohydrate diet. The primary outcomes compared mean daily ad libitum energy intake between each 2-week diet period as well as between the final week of each diet. We found that the low-fat diet led to 689 ± 73 kcal d
less energy intake than the low-carbohydrate diet over 2 weeks (P < 0.0001) and 544 ± 68 kcal d
less over the final week (P < 0.0001). Therefore, the predictions of the carbohydrate-insulin model were inconsistent with our observations. This study was registered on ClinicalTrials.gov as NCT03878108 .
Metabolic syndrome is a cluster of metabolic risk factors, characterized by abdominal obesity, dyslipidemia, low levels of high-density lipoprotein cholesterol (HDL-c), hypertension, and insulin ...resistance. Lifestyle modifications, especially dietary habits, are the main therapeutic strategy for the treatment and management of metabolic syndrome, but the most effective dietary pattern for its management has not been established. Specific dietary modifications, such as improving the quality of the foods or changing macronutrient distribution, showed beneficial effects on metabolic syndrome conditions and individual parameters. On comparing low-fat and restricted diets, the scientific evidence supports the use of the Mediterranean Dietary Approaches to Stop Hypertension (DASH) diet intervention as the new paradigm for metabolic syndrome prevention and treatment. The nutritional distribution and quality of these healthy diets allows health professionals to provide easy-to-follow dietary advice without the need for restricted diets. Nonetheless, energy-restricted dietary patterns and improvements in physical activity are crucial to improve the metabolic disturbances observed in metabolic syndrome patients.
Dietary modification remains key to successful weight loss. Yet, no one dietary strategy is consistently superior to others for the general population. Previous research suggests genotype or ...insulin-glucose dynamics may modify the effects of diets.
To determine the effect of a healthy low-fat (HLF) diet vs a healthy low-carbohydrate (HLC) diet on weight change and if genotype pattern or insulin secretion are related to the dietary effects on weight loss.
The Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) randomized clinical trial included 609 adults aged 18 to 50 years without diabetes with a body mass index between 28 and 40. The trial enrollment was from January 29, 2013, through April 14, 2015; the date of final follow-up was May 16, 2016. Participants were randomized to the 12-month HLF or HLC diet. The study also tested whether 3 single-nucleotide polymorphism multilocus genotype responsiveness patterns or insulin secretion (INS-30; blood concentration of insulin 30 minutes after a glucose challenge) were associated with weight loss.
Health educators delivered the behavior modification intervention to HLF (n = 305) and HLC (n = 304) participants via 22 diet-specific small group sessions administered over 12 months. The sessions focused on ways to achieve the lowest fat or carbohydrate intake that could be maintained long-term and emphasized diet quality.
Primary outcome was 12-month weight change and determination of whether there were significant interactions among diet type and genotype pattern, diet and insulin secretion, and diet and weight loss.
Among 609 participants randomized (mean age, 40 SD, 7 years; 57% women; mean body mass index, 33 SD, 3; 244 40% had a low-fat genotype; 180 30% had a low-carbohydrate genotype; mean baseline INS-30, 93 μIU/mL), 481 (79%) completed the trial. In the HLF vs HLC diets, respectively, the mean 12-month macronutrient distributions were 48% vs 30% for carbohydrates, 29% vs 45% for fat, and 21% vs 23% for protein. Weight change at 12 months was -5.3 kg for the HLF diet vs -6.0 kg for the HLC diet (mean between-group difference, 0.7 kg 95% CI, -0.2 to 1.6 kg). There was no significant diet-genotype pattern interaction (P = .20) or diet-insulin secretion (INS-30) interaction (P = .47) with 12-month weight loss. There were 18 adverse events or serious adverse events that were evenly distributed across the 2 diet groups.
In this 12-month weight loss diet study, there was no significant difference in weight change between a healthy low-fat diet vs a healthy low-carbohydrate diet, and neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss. In the context of these 2 common weight loss diet approaches, neither of the 2 hypothesized predisposing factors was helpful in identifying which diet was better for whom.
clinicaltrials.gov Identifier: NCT01826591.
Very-low-carbohydrate diets or ketogenic diets have been in use since the 1920s as a therapy for epilepsy and can, in some cases, completely remove the need for medication. From the 1960s onwards ...they have become widely known as one of the most common methods for obesity treatment. Recent work over the last decade or so has provided evidence of the therapeutic potential of ketogenic diets in many pathological conditions, such as diabetes, polycystic ovary syndrome, acne, neurological diseases, cancer and the amelioration of respiratory and cardiovascular disease risk factors. The possibility that modifying food intake can be useful for reducing or eliminating pharmaceutical methods of treatment, which are often lifelong with significant side effects, calls for serious investigation. This review revisits the meaning of physiological ketosis in the light of this evidence and considers possible mechanisms for the therapeutic actions of the ketogenic diet on different diseases. The present review also questions whether there are still some preconceived ideas about ketogenic diets, which may be presenting unnecessary barriers to their use as therapeutic tools in the physician's hand.
Background: Dietary strategies for weight loss include standard of care approaches such as daily caloric restriction (DCR) as well as novel alternatives such as intermittent fasting (IMF). Our ...objective was to evaluate changes in diet quality among individuals randomized to either DCR or modified IMF (mIMF) during a 1-year behavioral weight loss intervention. Methods: Adults with overweight or obesity without diabetes mellitus, cardiovascular disease, or chronic kidney disease (stage 4 or 5) were randomized to a 1-year behavioral weight loss intervention utilizing either DCR or mIMF (80% energy deficit, three non-consecutive days/week) as the dietary strategy. The targeted weekly dietary energy deficit was designed to be similar in DCR and mIMF (34%). Both intervention arms received group-based behavioral support including a recommendation to increase moderate-intensity physical activity to 300 min/week. Ninety-one individuals with complete 7-day diet records at baseline (BL) and 12 months (12 m) were included in this analysis (mean ± SD; age 42.6 ± 8.9 years, BMI 34.3 ± 4.5 kg/m2, 74% female, 88% White). Mean Healthy Eating Index (HEI) scores were calculated from 7-day diet records. Linear mixed models were used to examine the association between randomized group and change in outcomes over 1 year. Results are presented as mean ± SE. Results: Total HEI score was 54.9 ± 1.6 for DCR and 57.2 ± 1.5 for mIMF at BL and 57.0 ± 2.0 for DCR and 60.5 ± 1.9 for mIMF at 12 m. There were no significant changes in total HEI score within or between groups from BL to 12 m. Component scores for Total Fruit (+67%, p = 0.001) and Total Vegetables (+16%, p = 0.012) were improved from BL to 12 m in DCR, while score for Added Sugars (+7%, p = 0.021) was improved from BL to 12 m in mIMF. However, there were no between group differences in changes over time for any HEI components. Conclusions: Findings suggest neither DCR nor mIMF resulted in significant changes in diet quality although there were trends for improved adherence to recommendations for foods high in nutrient density and low in energy density, such as increased fruit and vegetable scores among those employing DCR and increased added sugar scores among those employing mIMF. Future work will evaluate if those exhibiting greater improvements in diet quality experience greater weight loss and/or improvements in clinical indicators of health.
Various nutritional therapies have been proposed in rheumatoid arthritis, particularly diets rich in ω-3 fatty acids, which may lead to eicosanoid reduction. Our aim was to investigate the effect of ...potentially anti-inflammatory diets (Mediterranean, vegetarian, vegan, ketogenic) on pain. The primary outcome was pain on a 10 cm visual analogue scale. Secondary outcomes were C-reactive protein levels, erythrocyte sedimentation rate, health assessment questionnaire, disease activity score 28, tender/swollen joint counts, weight, and body mass index. We searched MEDLINE (OVID), Embase (Elsevier), and CINAHL for studies published from database inception to 12 November 2021. Two authors independently assessed studies for inclusion, extracted study data, and assessed the risk of bias. We performed a meta-analysis with all eligible randomized controlled trials using RevMan 5. We used mean differences or standardized mean differences and the inverse variance method of pooling using a random-effects model. The search retrieved 564 unique publications, of which we included 12 in the systematic review and 7 in the meta-analysis. All studies had a high risk of bias and the evidence was very low. The main conclusion is that anti-inflammatory diets resulted in significantly lower pain than ordinary diets (-9.22 mm; 95% CI -14.15 to -4.29;
= 0.0002; 7 RCTs, 326 participants).
Background: The trajectory for weight change in diet and lifestyle interventions typically involves a period of rapid weight loss in the early stages of the intervention, followed by a weight plateau ...after approximately six months, and weight regain within a year or two. Changing from one weight loss diet type to another at the time of the plateau could instigate renewed weight loss. This secondary analysis aimed to assess the trajectory of weight loss in a 12-month, randomized, cross-over weight loss diet study comparing a healthy low-fat (HLF) with a healthy low-carbohydrate (HLC) diet among adults with overweight and obesity. Methods: Premenopausal women and men aged 18-50 years with BMI 28-40kg/m2 were randomized to eat either HLF or HLC diet for 6 months then switched to the opposite diet for an additional 6 months, with no washout period. Health educators supported adherence to study diets by delivering 7 diet-specific small group behavior modification sessions per phase. Sessions provided ways to achieve the lowest fat or carbohydrate intake that could be maintained long-term and emphasized diet quality. The primary outcome of this secondary analysis was weight change between (3-6 months) and (6-9 months). Results: Of the 60 participants that completed the primary 6 month parallel design study, 41 agreed to continue for the optional crossover and provided complete diet and weight data at 12 months. As anticipated, weight loss was greatest in the first three months of the first diet phase, regardless of diet assignment, and was modest in months 4-6. After switching diets at month 6, weight remained relatively stable until month 8, and at month 9 remained stable until month 12. Diet assessment indicated high adherence to both diets in both phases. Blood lipids provided objective confirmation of dietary adherence as changes in LDL-C, HDL-C, and triglycerides flipped in opposite directions for the second phase, as expected with diet assignment, despite general weight maintenance in the second phase. Conclusions: Overall, results indicated that switching diets did not significantly decrease weight beyond the initial 6 month mark. This would suggest that changing diets to address "diet fatigue" does not help with weight loss plateaus.
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