The Food and Nutrition Board (FNB) was established in 1940 to study issues of critical national importance pertaining to the safety and adequacy of the nation's food supply, to establish principles and guidelines for adequate nutrition, and to render authoritative judgment on the relationships among food intake, nutrition, and health. The FNB responds to requests from federal agencies and others to initiate studies concerning food and nutrition, assigns them to standing or ad hoc committees, then oversees the work of these committees. The FNB is a unit of the Institute of Medicine, part of the National Academy of Sciences.

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. Nearly one-third of adults in the United States are obese. Individuals wanting to lose weight have a wide variety of programs, services, and advice from which to choose, ranging from over-the-counter diet aids and community-based classes to commercial weight-loss centers and treatment by individual health-care providers. To date, however, few carefully derived sets of criteria have been available for evaluating the plethora of programs and approaches for the treatment and prevention of obesity in a systematic, comprehensive, and consistent manner.

Given the need to develop such criteria, the NAS provided the FNB with funding to conduct a 1-year study with the following objectives:

• Identify direct measurements of outcomes of obesity treatment and prevention programs as well as their priorities and special uses.

• Identify program characteristics that should be specified and measured in program evaluation.

• Identify appropriate uses of indirect measurements of outcomes (especially risk of specific diseases) of large-scale weight-loss programs.

• Identify characteristics that contribute to clients' choices of programs and their outcomes with these programs.  

• Identify the degree of weight loss needed to improve various health outcomes.

• Where information concerning these topics is limited, develop a specific agenda for research.

The Committee to Develop Criteria for Evaluating the Outcomes of Approaches to Prevent and Treat Obesity (hereafter termed the Obesity Committee), whose members wrote this report, consists of 10 scientists, most of whom are recognized leaders in obesity research and management. They work in a variety of settings, including public and private universities, medical schools, research centers, the federal government, and private practice. Brief biographies of the committee and project director can be found in Appendix E.

The committee met four times during the course of this study. Our draft report was formally reviewed under the auspices of the National Academy of Sciences' Report Review Committee by a panel of experts whose identities have not been revealed to the committee. In addition, members of the FNB reviewed the draft. The reviewers provided thoughtful, constructive critiques, and we have incorporated many of their suggestions in this report.

The focus of the report has been defined by the charges to the committee and our interpretation of them as well as the usual limits of time and resources. This report does not provide comprehensive descriptions and assessments of the various approaches to weight loss, nor does it discuss eating disorders such as anorexia or bulimia. In addition, we focused our work on obesity in adults and on obesity treatment rather than prevention. We have not neglected adolescent obesity and the prevention of obesity, but these are large topics that deserve special study by other committees.

This report has been prepared for a large audience, including biomedical researchers, clinicians, and public health specialists; individuals involved in the development, manufacture, or sale of weight-loss products and services; educators; federal, state, and local policymakers; and interested consumers. For the general public, a separate book on obesity and health, based on this report, is needed. That book would help readers evaluate the nature and causes of weight problems and help determine which, if any, type of weight-loss approach might be best for them and whether they need professional help.

This report would not have been possible without the help of the IOM staff. Special thanks go to our colleague Paul R. Thomas. Dr. Thomas

served as Project Director and editor of this report, and we relied heavily on his in-depth knowledge of nutrition and his excellent writing and editing skills. We also appreciate the help provided by Project Assistant Susan M. Knasiak, whose substantial computer, technical, and organizational skills facilitated the preparation of this manuscript and arrangements for our meetings, travel, and conference calls, and Sheila A. Moats, Research Associate, for her skills at reference identification and verification and help with planning a workshop and drafting a section of the report. Catherine E. Woteki, former director of the FNB, was instrumental in developing the proposal that led to this study and in efforts to obtain funding. We are very grateful to the Executive Committee of the Governing Board of the National Research Council, NAS, for agreeing to provide the necessary financial support.

During the course of this study, several nutrition professionals, biomedical scientists, government representatives, and representatives of the weight-loss industry contributed to discussions about the content of this report. Some provided material or advice at our invitation, some participated in a workshop held at our second meeting, and others responded to specific questions we posed. We are very thankful for their help and carefully considered all comments. We wish to single out the following individuals by name:

Representatives of government agencies: Joan M. Conway, U.S. Department of Agriculture; Karen A. Donato, National Institutes of Health (NIH); Katherine M. Flegal, National Center for Health Statistics (NCHS); Van S. Hubbard, NIH; Richard Kelly, Federal Trade Commission; Barbara J. Moore, NIH; and the Division of Health Examination Statistics, NCHS.

Representatives of the private sector: L. Arthur Campfield, Hoffmann-La Roche; Linda Webb Carilli, Weight Watchers International, Inc.; David J. Goldstein, Eli Lilly & Company (also affiliated with the Indiana University School of Medicine); Karen Miller-Kovach, Weight Watchers International, Inc.; Bruce F. Trumm II, Abbott Laboratories; and Brenda L. Wolfe, Jenny Craig, Inc.

Academics: Kelly D. Brownell, Yale University; Sally M. Davis, University of New Mexico School of Medicine, Albuquerque; Robert W. Jeffery, University of Minnesota, Minneapolis; and Rena R. Wing, University of Pittsburgh School of Medicine.

Others: Gail L. Kaye and Francis J. Peterson.

Very special thanks are due the three nutrition scientists who prepared background papers for the committee's use. George L. Blackburn, Chief of the Nutrition/Metabolism Laboratory at New England Deaconess

Hospital in Boston, prepared an algorithm of whom to treat for obesity and categories of treatment intensity. F. Xavier Pi-Sunyer, Chief of the Division of Endocrinology, Diabetes, and Nutrition at St. Luke's/Roosevelt Hospital Center in New York City, prepared a paper on the treatment of obesity with drugs; we used it to develop our statements and recommendations on the subject at various places in the report. Beatrice S. Kanders, an obesity specialist and now a private consultant in Atlanta, prepared a background paper on the prevention and treatment of obesity in childhood and adolescence. Because pediatric obesity is a very important subject that we were not able to address owing to time constraints, we have included an edited version of Dr. Kanders' paper in Appendix C.

We appreciate the assistance provided by the IOM's Reports and Information Office. Claudia Carl steered this report through formal review, and Mike Edington helped prepare the final manuscript for publication. Andrea Posner and Florence Poillon served ably as copy editors. Thanks are also due to the staff of the National Academy Press, particularly Sally Stanfield, Barbara Kline Pope, and Christine Chirichella, for their help in publishing and marketing the report and for their patience with us. Our acknowledgments would not be complete without thanking Kenneth I. Shine, IOM President; Enriqueta C. Bond, former IOM Executive Officer; Joseph S. Cassells, Interim IOM Executive Officer; Bernadette M. Marriott; Allison A. Yates; and the members of the FNB for their support, advice, and encouragement throughout the short life of this fast-track study.

Finally, as chair, I would like to thank my fellow committee members for their hard work and good cheer in meeting what often seemed to be impossible deadlines.