In an older discussion on this issue, travisp shared this article: http://jama.jamanetwork.com/article.aspx?articleid=1199154 http://jama.jamanetwork.com/articl

In an older discussion on this issue, travisp shared this article: http://jama.jamanetwork.com/article.aspx?articleid=1199154 http://jama.jamanetwork.com/article.aspx?articleid=1199154 >Effects of Dietary Composition on Energy Expenditure During Weight-Loss Maintenance > "The results of our study challenge the notion that a calorie is a calorie from a metabolic perspective. During isocaloric feeding ... total energy expenditure differed by approximately 300 kcal/d between very-low-carb and low-fat diets, an effect corresponding with the amount of energy typically expended in 1 hour of moderate-intensity physical activity." "In conclusion, our study demonstrates that commonly consumed diets can affect metabolism and components of the metabolic syndrome in markedly different ways during weight-loss maintenance, independent of energy content. The low-fat diet produced changes in energy expenditure and serum leptin42- 44 that would predict weight regain. In addition, this conventionally recommended diet had unfavorable effects on most of the metabolic syndrome components studied herein."