First-Ever Obesity Clinical Guidelines Released
About 97 million Americans are overweight and obese, putting them at an increased risk for cardiovascular and other diseases, including hypertension and diabetes.
Recently, NHLBI, in cooperation with NIDDK, released the first federal "Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults." The guidelines are designed to help clinicians evaluate and treat patients and were developed by a 24-member expert panel. The panel was chaired by Dr. F. Xavier Pi-Sunyer, director of the Obesity Research Center at St. Luke's/Roosevelt Hospital Center in New York City.
The guidelines' development used a rigorous "evidence-based" approach, which involved a systematic analysis of research. To develop the evidence model, the panel posed 35 key clinical questions such as, "What is the evidence that weight loss directly affects high blood pressure?" The scientific literature published in MEDLINE from 1980-97 was then searched and repeatedly screened. This led to the development of evidence tables, on which the panel based its recommendations.
The evidence model was chosen in order to conduct a thorough review of the scientific literature and also to produce guidelines that would give clinicians as much information and flexibility as possible. The guidelines document how different treatment strategies affect weight loss and how weight control affects the major risk factors for heart disease and stroke.
The guidelines' release resulted in widespread media coverage, much of it focusing on the panel's recommendation that clinicians use the body mass index (BMI) to help define overweight and obese. After reviewing the evidence on the health risks associated with an increasing BMI, the panel defined overweight as a BMI of 25-29.9 and obese as a BMI of 30 or more. The definitions apply to men and women, although some very muscular people may have a high BMI without added health risks. The definitions are used by many organizations, including the World Health Organization and the American Heart Association, and support the BMI definitions in the 1995 Dietary Guidelines for Americans.
The guidelines recommend that persons with a BMI of 25-29.9 but no other cardiovascular disease risk factors not gain weight. The panel advises weight loss for persons who have a BMI of 25 or greater and two or more obesity-related risk factors such as hypertension and diabetes.
The panel reserves drug therapy for those who are obese or who have a BMI of 27 or above and two or more other concomitant obesity-related risk factors and only after at least 6 months of nondrug therapy. The panel says drug therapy may be used only in combination with diet and physical activity, and that appropriate patient followup should be conducted.
The guidelines note that the most successful weight loss strategies include calorie reduction, increased physical activity, and behavior therapy to improve eating and physical activity habits.
To change behaviors, the guidelines suggest patients focus on simple ways to break old habits and develop new, healthier ones. For instance, while fat matters, calories count, and Americans should be careful not to over-eat low fat products, thus tipping the balance of energy intake versus energy expenditure.
The guidelines also recommend 30 minutes or more of moderate physical activity on most or preferably all days of the week, an initial weight loss for those in treatment of about 10 percent of body weight, a loss of no more than 1 to 2 pounds per week, and making weight maintenance be a priority after the first 6 months of weight-loss therapy.
NIH'ers can find their BMI by using the special calculator on the NHLBI Web site at http://www.nhlbi.nih.gov/nhlbi/. Besides the calculator, the site has the guidelines -- in their full and executive summary forms -- the press release, evidence tables, BMI tables, consumer nutrition tipsheets and more.
Or write to the NHLBI Information Center, P. O. Box 30105, Bethesda, MD 20824-0105. Single copies of the executive summary and the consumer tipsheets are available free. The full guidelines will be published in the September issue of the journal Obesity Research and the executive summary is expected to appear in the September issue of the Archives of Internal Medicine.
NHLBI also is collaborating with the North American Association for the Study of Obesity to produce a practical guide version of the guidelines, which will be distributed to primary care doctors and others who treat overweight and obese people.
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