Popular weight-loss plans often have conflicting recommendations, which makes it difficult to determine the most healthful approach to weight loss. Our study compares the dietary quality of popular weight-loss plans. Dietary quality, measured by the Alternate Healthy Eating Index (AHEI), was calculated via sample menus provided in published media for the New Glucose Revolution, Weight Watchers, Atkins, South Beach, Zone, Ornish, and 2005 US Department of Agriculture Food Guide Pyramid (2005 Food Guide Pyramid) plans. The criterion for determining which weight-loss plans were the most popular was their status on the New York Times Bestseller list. Weight Watchers and the 2005 Food Guide Pyramid plan were included because they are the largest commercial weight-loss plan, and the current government recommendation, respectively. Analysis of variance was used to compare nutrient information among the weight-loss plans. The AHEI scores adjusted for energy content were also compared. Of a maximum possible score of 70, the AHEI scores for each weight-loss plan from the highest to the lowest plan were: Ornish (score 64.6), Weight Watchers high-carbohydrate (score 57.4), New Glucose Revolution (score 57.2), South Beach/Phase 2 (score 50.7), Zone (score 49.8), 2005 Food Guide Pyramid (score 48.7), Weight Watchers high-protein (score 47.3), Atkins/100-g carbohydrate (score 46), South Beach/Phase 3 (score 45.6), and Atkins/45-g carbohydrate (score 42.3). Dietary quality varied across popular weight-loss plans. Ornish, Weight Watchers high-carbohydrate, and New Glucose Revolution weight-loss plans have an increased capacity for cardiovascular disease prevention when assessed by the AHEI.