To assist health professionals who counsel patients with overweight and obesity, a systematic review was undertaken to determine types of weight-loss interventions that contribute to successful outcomes and to define expected weight-loss outcomes from such interventions.
A search was conducted for weight-loss–focused randomized clinical trials with ≥1-year follow-up. Eighty studies were identified and are included in the evidence table.
The primary outcomes were a measure of weight loss at 6, 12, 24, 36, and 48 months. Eight types of weight-loss interventions—diet alone, diet and exercise, exercise alone, meal replacements, very-low-energy diets, weight-loss medications (orlistat and sibutramine), and advice alone—were identified. By using simple pooling across studies, subjects mean amount of weight loss at each time point for each intervention was determined.
Statistical analyses performed
Efficacy outcomes were calculated by meta-analysis and provide support for the pooled data. Hedges’ gu was combined across studies to obtain an average effect size (and confidence level).
A mean weight loss of 5 to 8.5 kg (5% to 9%) was observed during the first 6 months from interventions involving a reduced-energy diet and/or weight-loss medications with weight plateaus at approximately 6 months. In studies extending to 48 months, a mean 3 to 6 kg (3% to 6%) of weight loss was maintained with none of the groups experiencing weight regain to baseline. In contrast, advice-only and exercise-alone groups experienced minimal weight loss at any time point.
Weight-loss interventions utilizing a reduced-energy diet and exercise are associated with moderate weight loss at 6 months. Although there is some regain of weight, weight loss can be maintained. The addition of weight-loss medications somewhat enhances weight-loss maintenance.
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M. J. Franz is a nutrition/health consultant with Nutrition Concepts by Franz, Inc, Minneapolis, MN.
J. J. VanWormer is a program evaluation consultant at HealthPartners Health Behavior Group, Minneapolis, MN.
A. L. Crain is a statistician at HealthPartners Research Foundation, Minneapolis, MN.
J. L. Boucher is director of education, Minneapolis Heart Institute Foundation, Minneapolis; at the time of the study, she was director, Health Programs and Performance Measurement, HealthPartners Health Behavior Group, Minneapolis, MN.
T. Histon is director of weight management initiative and W. Caplan is director of clinical development at Kaiser Permanente’s Care Management Institute, Oakland, CA.
J. D. Bowman is manager of knowledge and information at A. Kaiser Permanente Innovation, Oakland, CA.
N. P. Pronk is executive director, HealthPartners Health Behavior Group, Minneapolis, MN.
© 2007 American Dietetic Association. Published by Elsevier Inc. All rights reserved.