Dislike of the diet is a common complaint in weight loss therapy that contributes to poor outcomes. Ironically, individual food preferences are rarely taken into account in designing weight-loss interventions. In the proposed research, we will utilize genetically-determined differences in food preferences, indexed by PROP bitter taste phenotype to develop a novel approach to weight loss therapy. The overall goal of this project is to determine if weight loss following a 6 month intervention can be substantially improved by matching participants with diets that reflect their genetically-determined food preferences. The study is designed as a randomized clinical weight-loss intervention trial in women in which PROP non-tasters and super-tasters. will be randomized to either the low-carbohydrate or the low-fat diet condition