Obesity is a major contributor to m...

Obesity is a major contributor to morbidity and mortality in the United States. In fresh years, low-carbohydrate diets have attracted increasing interest as a means of losing weight. However, questions about the long-term efficacy and safety of low-carbohydrate diets remain. Specifically, businesss have been raised about the accumulation of ketones and impaired liver and kidney function, salt and water depletion, and excessive consumption of animal proteins and fats. Bravata and colleagues examined the medical literature onward low-carbohydrate diets.

A MEDLINE search of English-language studies published between January 1 1966 and February 15 2003 identified 2609 titles and abstracts. Bivariate analyses estimated the differences in weight los serum lipid evens fasting serum glucose levels, fasting serum insulin of the same heights and blood pressure between sum of two units groups participating in lower and higher carbohydrate diets. The authors characterized diets as lowest carbohydrate diets (up to 20 g by means of day), lower carbohydrate diets (between 21 and 60 g for day), and higher carbohydrate diets (more than 60 g by means of day).

A total of 107 studies met the authors' inclusion criteria. investigation designs were highly heterogeneous. The lower carbohydrate diets were generally of shorter duration than the higher carbohydrate diets; solely five studies of low-carbohydrate diets lasted more than 90 days, and none of these was randomized or controll Lower carbohydrate diets had fewer calories than higher carbohydrate diets.

The authors lay the foundation of that the greatest weight los was achieved at participants who took in the fewest calories, regardless of carbohydrate contentment In 34 of 38 lower carbohydrate diets, weight los appeared to be greater than in higher carbohydrate diets, if it were not that when only the randomized controll trials were included in the analysis, the difference between these diets was not statistically significant. In 13 studies of lowest carbohydrate diets, the heterogeneity of contemplation design led the authors to bring to an end that the 1.2 kg (26 lb) weight change associated with these diets was not statistically significant. In the studies demonstrating the greatest weight los participants were significantly overweight at baseline, and the diets were longer in duration and in restricted caloric intake. In general, no change was noted in serum lipid plains fasting glucose levels, or offspring pressure.

Bravata and colleagues finish that there is insufficient evidence to make recommendations onward low-carbohydrate diets because studies were short-term, have included simply certain types of patients, and have not adequately measured biologic indexes. Caloric restriction and diet duration correlated with weight los moreover the authors found insufficient evidence to determine that low-carbohydrate diets independently bring forward more weight loss than higher carbohydrate diets. There is a ne for studies of isocaloric diets that compare different carbohydrate peaces Lower carbohydrate diets may be effective in achieving weight los across the short-term without compromising health, as measured by the agency of effects on glucose and lipid on a levels and blood pressure. This conclusion does not apply to bodys with diabetes, nor can any statements or recommendations be made for longer limit use of these diets.

CAROLINE WELLBERY, MD

Bravata DM et al. Efficacy and safety of low-carbohydrate diets. A systematic review. JAMA April 9 2003;289:1837-50

COPYRIGHT 2003 American Academy of Family Physicians

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