Background: There is evidence that reducing blood glucose concentrations, inducing weight loss, and improving the lipid profile reduces cardiovascular risk in people with type 2 diabetes.Objective: ...We assessed the effect of various diets on glycemic control, lipids, and weight loss.Design: We conducted searches of PubMed, Embase, and Google Scholar to August 2011. We included randomized controlled trials (RCTs) with interventions that lasted ≥6 mo that compared low-carbohydrate, vegetarian, vegan, low–glycemic index (GI), high-fiber, Mediterranean, and high-protein diets with control diets including low-fat, high-GI, American Diabetes Association, European Association for the Study of Diabetes, and low-protein diets.Results: A total of 20 RCTs were included (n = 3073 included in final analyses across 3460 randomly assigned individuals). The low-carbohydrate, low-GI, Mediterranean, and high-protein diets all led to a greater improvement in glycemic control glycated hemoglobin reductions of −0.12% (P = 0.04), −0.14% (P = 0.008), −0.47% (P < 0.00001), and −0.28% (P < 0.00001), respectively compared with their respective control diets, with the largest effect size seen in the Mediterranean diet. Low-carbohydrate and Mediterranean diets led to greater weight loss −0.69 kg (P = 0.21) and −1.84 kg (P < 0.00001), respectively, with an increase in HDL seen in all diets except the high-protein diet.Conclusion: Low-carbohydrate, low-GI, Mediterranean, and high-protein diets are effective in improving various markers of cardiovascular risk in people with diabetes and should be considered in the overall strategy of diabetes management.
Accumulating evidence suggests that some dietary patterns, specifically high fat diet (HFD), increase the risk of developing sporadic Alzheimer disease (AD). Thus, interventions targeting HFD-induced ...metabolic dysfunctions may be effective in preventing the development of AD. We previously demonstrated that amyloid precursor protein (APP)-overexpressing transgenic mice fed HFD showed worsening of cognitive function when compared with control APP mice on normal diet. Moreover, we reported that voluntary exercise ameliorates HFD-induced memory impairment and β-amyloid (Aβ) deposition. In the present study, we conducted diet control to ameliorate the metabolic abnormality caused by HFD on APP transgenic mice and compared the effect of diet control on cognitive function with that of voluntary exercise as well as that of combined (diet control plus exercise) treatment. Surprisingly, we found that exercise was more effective than diet control, although both exercise and diet control ameliorated HFD-induced memory deficit and Aβ deposition. The production of Aβ was not different between the exercise- and the diet control-treated mice. On the other hand, exercise specifically strengthened the activity of neprilysin, the Aβ-degrading enzyme, the level of which was significantly correlated with that of deposited Aβ in our mice. Notably, the effect of the combination treatment (exercise and diet control) on memory and amyloid pathology was not significantly different from that of exercise alone. These studies provide solid evidence that exercise is a useful intervention to rescue HFD-induced aggravation of cognitive decline in transgenic model mice of AD.
Background: Exercise and diet control are fundamental approaches to metabolic conditions caused by high fat diet (HFD).
Results: HFD-induced memory deficit and Aβ deposition were more ameliorated in the exercise- than in the diet control-induced mice.
Conclusion: Exercise was more effective than diet control in preventing HFD-induced AD development.
Significance: Exercise has the highest priority in the prevention of AD.
The ketogenic diet (KD) is a high-fat, adequate-protein, and very-low-carbohydrate diet regimen that mimics the metabolism of the fasting state to induce the production of ketone bodies. The KD has ...long been established as a remarkably successful dietary approach for the treatment of intractable epilepsy and has increasingly garnered research attention rapidly in the past decade, subject to emerging evidence of the promising therapeutic potential of the KD for various diseases, besides epilepsy, from obesity to malignancies. In this review, we summarize the experimental and/or clinical evidence of the efficacy and safety of the KD in different diseases, and discuss the possible mechanisms of action based on recent advances in understanding the influence of the KD at the cellular and molecular levels. We emphasize that the KD may function through multiple mechanisms, which remain to be further elucidated. The challenges and future directions for the clinical implementation of the KD in the treatment of a spectrum of diseases have been discussed. We suggest that, with encouraging evidence of therapeutic effects and increasing insights into the mechanisms of action, randomized controlled trials should be conducted to elucidate a foundation for the clinical use of the KD.
Growing evidence shows that a dietary pattern inspired by Mediterranean dietprinciples is associated with numerous health benefits. A Mediterranean-typediet has been demonstrated to exert a ...preventive effect toward cardiovasculardiseases, in both Mediterranean and non-Mediterranean populations. Part ofthese properties may depend on a positive action toward healthier metabolism,decreasing the risk of diabetes and metabolic-syndrome-related conditions.Some studies also suggested a potential role in preventing certain cancers. Finally,newer research has showed that a higher adherence to the Mediterranean diet isassociated with a lower risk of cognitive decline, depression, and other mentaldisorders. Overall, a better understanding of the key elements of this dietarypattern, the underlying mechanisms, and targets, are needed to corroboratecurrent evidence and provide insights on new and potential outcomes.ThisSpecial Issue welcomes original research and reviews of literature concerningthe Mediterranean diet and various health outcomes:Observational studies onestablished nutritional cohorts (preferred), case-control studies, or populationsample on the association with non-communicable diseases;Level of evidenceon the association with human health, including systematic reviews and metaanalyses;Evaluation of application of Mediterranean diet principles in non-Mediterranean countries;Description of mechanisms of action, pathways, andtargets at the molecular level, including interaction with gut microbiota.
In the past, different types of diet with a generally low-carbohydrate content (< 50–< 20 g/day) have been promoted, for weight loss and diabetes, and the effectiveness of a very low dietary ...carbohydrate content has always been a matter of debate. A significant reduction in the amount of carbohydrates in the diet is usually accompanied by an increase in the amount of fat and to a lesser extent, also protein. Accordingly, using the term “low carb–high fat” (LCHF) diet is most appropriate. Low/very low intakes of carbohydrate food sources may impact on overall diet quality and long-term effects of such drastic diet changes remain at present unknown. This narrative review highlights recent metabolic and clinical outcomes of studies as well as practical feasibility of low LCHF diets. A few relevant observations are as follows: (1) any diet type resulting in reduced energy intake will result in weight loss and related favorable metabolic and functional changes; (2) short-term LCHF studies show both favorable and less desirable effects; (3) sustained adherence to a ketogenic LCHF diet appears to be difficult. A non-ketogenic diet supplying 100–150 g carbohydrate/day, under good control, may be more practical. (4) There is lack of data supporting long-term efficacy, safety and health benefits of LCHF diets. Any recommendation should be judged in this light. (5) Lifestyle intervention in people at high risk of developing type 2 diabetes, while maintaining a relative carbohydrate-rich diet, results in long-term prevention of progression to type 2 diabetes and is generally seen as safe.
American eating changed dramatically in the early twentieth century. As food production became more industrialized, nutritionists, home economists, and so-called racial scientists were all pointing ...Americans toward a newly scientific approach to diet. Food faddists were rewriting the most basic rules surrounding eating, while reformers were working to reshape the diets of immigrants and the poor. And by the time of World War I, the country's first international aid program was bringing moral advice about food conservation into kitchens around the country. InModern Food, Moral Food, Helen Zoe Veit argues that the twentieth-century food revolution was fueled by a powerful conviction that Americans had a moral obligation to use self-discipline and reason, rather than taste and tradition, in choosing what to eat.Veit weaves together cultural history and the history of science to bring readers into the strange and complex world of the American Progressive Era. The era's emphasis on science and self-control left a profound mark on American eating, one that remains today in everything from the ubiquity of science-based dietary advice to the tenacious idealization of thinness.
Aims/hypothesis
Weight reduction is fundamental for type 2 diabetes management and remission, but uncertainty exists over which diet type is best to achieve and maintain weight loss. We evaluated ...dietary approaches for weight loss, and remission, in people with type 2 diabetes to inform practice and clinical guidelines.
Methods
First, we conducted a systematic review of published meta-analyses of RCTs of weight-loss diets. We searched MEDLINE (Ovid), PubMed, Web of Science and Cochrane Database of Systematic Reviews, up to 7 May 2021. We synthesised weight loss findings stratified by diet types and assessed meta-analyses quality with A Measurement Tool to Assess Systematic Reviews (AMSTAR) 2. We assessed certainty of pooled results of each meta-analysis using Grading of Recommendations, Assessment, Development and Evaluations (GRADE) (PROSPERO CRD42020169258). Second, we conducted a systematic review of any intervention studies reporting type 2 diabetes remission with weight-loss diets, in MEDLINE (via PubMed), Embase and Cochrane Central Register of Controlled Trials, up to 10 May 2021. Findings were synthesised by diet type and study quality (Cochrane Risk of Bias tool 2.0 and Risk Of Bias In Non-randomised Studies – of Interventions ROBINS-I), with GRADE applied (PROSPERO CRD42020208878).
Results
We identified 19 meta-analyses of weight-loss diets, involving 2–23 primary trials (
n
= 100–1587), published 2013–2021. Twelve were ‘critically low’ or ‘low’ AMSTAR 2 quality, with seven ‘high’ quality. Greatest weight loss was reported with very low energy diets, 1.7–2.1 MJ/day (400–500 kcal) for 8–12 weeks (high-quality meta-analysis, GRADE low), achieving 6.6 kg (95% CI −9.5, −3.7) greater weight loss than low-energy diets (4.2–6.3 MJ/day 1000–1500 kcal). Formula meal replacements (high quality, GRADE moderate) achieved 2.4 kg (95% CI −3.3, −1.4) greater weight loss over 12–52 weeks. Low-carbohydrate diets were no better for weight loss than higher-carbohydrate/low-fat diets (high quality, GRADE high). High-protein, Mediterranean, high-monounsaturated-fatty-acid, vegetarian and low-glycaemic-index diets all achieved minimal (0.3–2 kg) or no difference from control diets (low to critically low quality, GRADE very low/moderate). For type 2 diabetes remission, of 373 records, 16 met inclusion criteria. Remissions at 1 year were reported for a median 54% of participants in RCTs including initial low-energy total diet replacement (low-risk-of-bias study, GRADE high), and 11% and 15% for meal replacements and Mediterranean diets, respectively (some concerns for risk of bias in studies, GRADE moderate/low). For ketogenic/very low-carbohydrate and very low-energy food-based diets, the evidence for remission (20% and 22%, respectively) has serious and critical risk of bias, and GRADE certainty is very low.
Conclusions/interpretation
Published meta-analyses of hypocaloric diets for weight management in people with type 2 diabetes do not support any particular macronutrient profile or style over others. Very low energy diets and formula meal replacement appear the most effective approaches, generally providing less energy than self-administered food-based diets. Programmes including a hypocaloric formula ‘total diet replacement’ induction phase were most effective for type 2 diabetes remission. Most of the evidence is restricted to 1 year or less. Well-conducted research is needed to assess longer-term impacts on weight, glycaemic control, clinical outcomes and diabetes complications.
Graphical abstract
Summary
The most appropriate type of diets to maintain or lose body weight over the medium to long term has been a matter of controversy and debates for more than half a century. Both voluntarily and ...coercive food restriction, resulting in negative energy and macronutrient balance and hence weight loss, have not been designed to be maintained for the long term. By contrast, when a classical and traditional type of alimentation is consumed in ad lib conditions (e.g., the Mediterranean “diet”), it generally provides an appropriate nutritional density of essential macronutrients and micronutrients; it is hence appropriate for long‐term use, and it provides several benefits for health if the compliance of the individuals is maintained over time. In this short review, we focus on four specific aspects: first, the need to agree on a clear definition of what is “low” versus “high” in terms of total carbohydrate intake and total fat intakes, both generally inversely related, in a representative individual with a certain lifestyle and a certain body morphology; second, the importance of discussing the duration over which it could be prescribed, that is, acute versus chronic conditions, focusing on the comparison between the fashion and often ephemeral low‐carbohydrate diet (acute) with the well‐recognized traditional Mediterranean type of alimentation (chronic), which includes lifestyle changes; third, the particular metabolic characteristics induced by the low‐carbohydrate (high fat) diet, namely, the scramble up of ketone bodies production. The recent debate on ketogenic diets concern whether or not, in iso‐energetic conditions, low‐carbohydrate diets would significantly enhance energy expenditure. This is an issue that is more “academic” than practical, on the ground that the putative difference of 100–150 kcal/day or so (in the recent studies) is not negligible but within the inherent error of the methodology used to track total energy expenditure in free living conditions by the doubly labeled water technique. Fourth, the potential medical risks and shortcomings of ingesting (over the long term) low‐carbohydrate ketogenic diets could exacerbate underlying renal dysfunction, consecutive to the joint combination of high‐fat, high‐protein diets, particularly in individuals with obesity. This particular diet promotes metabolic acidosis and renal hyperfiltration, which ultimately may contribute to a significant reduction in life expectancy in middle‐age people.
Despite being a focal issue to patients, the effect of diet on adult inflammatory bowel disease (IBD) remains underexplored with limited guidance. While promising clinical trials are currently ...underway, there is a need for further evidence-based recommendations. As such, we summarize the current evidence on various diets used in the treatment of IBD and also explore the potential applications of dietary data from related immune-mediated inflammatory diseases (IMIDs), such as rheumatoid arthritis and psoriasis, to provide additional information to inform IBD providers. To date, there have been multiple diets investigated as adjunctive therapy in IBD, but many associated studies are small, non-randomized, and not controlled. Mediterranean, vegetarian/vegan, and reduced-calorie/fasting diets have been studied and have shown some positive results in other IMIDs, which may suggest potential applicability to those with IBD, but larger, well-designed clinical trials are needed for further guidance. Gluten-free and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP)diets do not appear to have an impact on IBD disease activity, but low FODMAP may potentially be helpful for those with concurrent functional gastrointestinal symptoms. Specific carbohydrate diets have been mainly assessed in children but show some potential in small adult studies.
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