Authors' objectives:

To assess the scientific evidence underlying the interventions against obesity in adults and children. The Project Group reviewed the evidence for preventive interventions and a range of treatment methods, including diet, exercise, behavioral therapy, medications, alternative medicine, and surgery.

Authors' recommendations: Most population-based preventive programs that have been scientifically assessed have not demonstrated any favorable effects on the prevalence of obesity. However, there are examples of successful programs for both adults and children. New outreach strategies eg, to disseminate the latest information about the causes and risks of obesity and to change dietary habits and motivate individuals to become more physical active need to be developed and assessed. Concurrently, public policy initiatives are needed to reduce the incidence of obesity. Scientific assessments of treatment methods for obesity show that: - Changes in dietary habits through counseling (mainly reduction of energy and fat intake) can lead to weight reduction, as a rule in the range of 3 to 10 kg during the first year (or 10% of body weight in children). The long-term effects are uncertain. - Regular exercise contributes to weight reduction. - Behavioral therapy in conjunction with changes in diet and exercise can have further effects on weight if supportive interventions continue for a longer period. - Approximately one fifth of those who undergo treatment based on the weight watcher approach, and reach their goals, achieve a permanent weight loss of 10% or more of their original weight. - VLCD for 6 to 12 weeks yields a greater weight reduction than conventional low energy diets. In studies of VLCD for 1 to 2 years, where the treatment was often periodic, authors note a retained weight loss of a few kilograms more than in treatment using a balanced diet alone (VLCD = Very Low Calorie Diet, based on protein formulas). - Pharmacological treatment using orlistat (Xenical) or sibutramine (Reductil) yields an average weight loss of 2 to 5 kg beyond that which would be attained through diet and exercise alone. In clinical trials, one fourth to one fifth of those who started pharmacological treatment lost at least 10% in weight compared to half as many of those treated with placebo. - The major problem is that weight loss is not usually permanent. Within a few years most who had initially succeeded in losing weight had returned to their original weight. Therefore, it is particularly important to develop and assess long-term treatments that aim at permanent weight loss. - Surgical treatment, which is an option in severely obese patients, reduces weight, on average, by somewhat more than 25% (eg, from 125 to 90 kg) up to 5 years after surgery. After 10 years, a weight loss of approximately 16% remains, on average slightly over 20 kg. This has substantial health and quality of life benefits for this patient group. The intervention, however, carries risks for complications. - The scientific evidence for a wide range of alternative medicine methods is too weak to draw any conclusions concerning the possible effects which these methods have on obesity. The risks of obesity can be reduced through weight reduction, regardless of the methods used. Intervening against other risk factors even when weight reduction does not succeed can help reduce the risks of obesity. Such interventions would include increased physical activity, smoking cessation, and improved control of diabetes, high blood pressure, and elevated blood lipids.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.sbu.se/Published

Year Published: 2002

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Sweden

Organisation Name: Swedish Agency for Health Technology Assessment and Assessment of Social Services

Contact Address: P.O. Box 3657, SE-103 59 Stockholm, Sweden. Tel: +46 8 4123200, Fax: +46 8 4113260

Contact Name: registrator@sbu.se

Contact Email: registrator@sbu.se

Copyright: Swedish Council on Technology Assessment in Health Care (SBU)