[Systematic review of weight loss diets: role of dietary components].

Being overweight is the sixth most important risk factor for chronic non-transmissible diseases. Many publications have been produced in recent years to evaluate the best weight loss alternative. The aim of this systematic review was to critically assess the role of dietary components (macronutrients and/or foods) in weight loss diets in adults recently described in the literature. Randomized clinical trials, with at least one year of follow-up, were selected in MedLine (in Portuguese, English and Spanish languages) from 2004 to 2009. Among the 23 studies included with different types of diets, 13 presented a rate of withdrawal from the study > or = 25% in at least one of the diets. In conclusion, most diets where the weight loss was > 5% of initial weight were energy restricted. Furthermore, following low carbohydrate or Mediterranean diets can be an alternative to isolated energy restriction, but these data are yet to be confirmed.