For several years, the Food and Nutrition Board (FNB) of the Institute of Medicine (IOM), National Academy of Sciences (NAS) has wished to develop criteria that could be used by others to evaluate the effectiveness of various approaches to preventing and treating the problems of overweight and obesity. The NAS provided the FNB with funding to conduct a 1-year study with the following objectives: (1) Identify direct measurements of outcomes of obesity treatment and prevention programs as well as their priorities and special uses. (2) Identify program characteristics that should be specified and measured in program evaluation. (3) Identify appropriate uses of indirect measurements of outcomes (especially risk of specific diseases) of large-scale weight-loss programs. (4) Identify characteristics that contribute to clients' choices of programs and their outcomes with these programs. (5) Identify the degree of weight loss needed to improve various health outcomes. (6) Where information concerning these topics is limited, develop a specific agenda for research. This book reports on the study findings, resulting in the FNB's new criteria for evaluating the effectiveness of programs to treat and prevent obesity. (PsycINFO Database Record (c) 2004 APA, all rights reserved).