Weight-loss outcomes: a systematic review and meta-analysis of weight-loss clinical trials with a minimum 1-year follow-up.
OBJECTIVE
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.


METHODS
A search was conducted for weight-loss-focused randomized clinical trials with >or=1-year follow-up. Eighty studies were identified and are included in the evidence table.


METHODS
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.


METHODS
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).


RESULTS
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.


CONCLUSIONS
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.
Franz
Marion J
MJ
Nutrition Concepts by Franz, Inc, Minneapolis, MN 55439, USA. MarionFranz@aol.com
VanWormer
Jeffrey J
JJ
Crain
A Lauren
AL
Boucher
Jackie L
JL
Histon
Trina
T
Caplan
William
W
Bowman
Jill D
JD
Pronk
Nicolas P
NP
D000328:Adult; D019440:Anti-Obesity Agents / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D003503:Cyclobutanes / Q000627:therapeutic use; D004038:Diet, Reducing; D015444:Exercise / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D005526:Food, Formulated; D006801:Humans; D007783:Lactones / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000178:diet therapy / Q000188:drug therapy / Q000628:therapy*; D000077403:Orlistat; D016896:Treatment Outcome; D015431:Weight Loss
D019440:Anti-Obesity Agents; D003503:Cyclobutanes; D007783:Lactones; D000077403:Orlistat; C058254:sibutramine