Effects of Popular Diets without Specific Calorie Targets on Weight Loss Outcomes: Systematic Review of Findings from Clinical Trials.

Nutrients. 2017;9(8)
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Calorie-restricted diets have not been highly successful in reducing obesity levels. This has led to an increased interest in alternative dietary approaches to achieve sustained weight loss. The purpose of this systematic review was to analyse the most popular diets of 2016 for short- and long-term weight loss outcomes based on findings from clinical trials that do not include calorie restriction or increased physical activity levels. Of all existing literature, only 16 articles met the inclusion criteria covering 7 popular diets, indicating the lack of clinical trials and high-quality evidence. The Atkins diet is the most well-researched popular diet and demonstrates substantial long-term weight loss. The Paleolithic diet has also been found to produce sustained weight loss according to the one study included on this diet. Based to these findings, the authors conclude that of the popular diets, those with a low carbohydrate component seem to be effective, though the safety of these diets has not been critically examined. Further evidence is needed to provide a more comprehensive evaluation of the efficacy of each of these popular diets.

Abstract

The present review examined the evidence base for current popular diets, as listed in the 2016 U.S. News & World Report, on short-term (≤six months) and long-term (≥one year) weight loss outcomes in overweight and obese adults. For the present review, all diets in the 2016 U.S. News & World Report Rankings for "Best Weight-Loss Diets", which did not involve specific calorie targets, meal replacements, supplementation with commercial products, and/or were not categorized as "low-calorie" diets were examined. Of the 38 popular diets listed in the U.S. News & World Report, 20 met our pre-defined criteria. Literature searches were conducted through PubMed, Cochrane Library, and Web of Science using preset key terms to identify all relevant clinical trials for these 20 diets. A total of 16 articles were identified which reported findings of clinical trials for seven of these 20 diets: (1) Atkins; (2) Dietary Approaches to Stop Hypertension (DASH); (3) Glycemic-Index; (4) Mediterranean; (5) Ornish; (6) Paleolithic; and (7) Zone. Of the diets evaluated, the Atkins Diet showed the most evidence in producing clinically meaningful short-term (≤six months) and long-term (≥one-year) weight loss. Other popular diets may be equally or even more effective at producing weight loss, but this is unknown at the present time since there is a paucity of studies on these diets.

Lifestyle medicine

Fundamental Clinical Imbalances : Hormonal ; Digestive, absorptive and microbiological
Patient Centred Factors : Mediators/Diet
Environmental Inputs : Diet ; Nutrients
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Not applicable

Methodological quality

Allocation concealment : Not applicable
Publication Type : Journal Article ; Review ; Systematic Review

Metadata

Nutrition Evidence keywords : Popular diets ; Atkins diet ; Weight loss ; Low-carbohydrate diet