Wadden · The New England journal of medicine 2005 · randomized controlled trial · n=224

Randomized trial of lifestyle modification and pharmacotherapy for obesity.

Cited 799 times in the scientific literature.

Level 2 - randomized trial

Individual randomized controlled trial

PubMed 16291981 · doi:10.1056/NEJMoa050156 · record verified 2026-08-28

What was done

A 1-year randomized controlled trial evaluated 224 obese adults assigned to one of four interventions: (1) 15 mg/day sibutramine alone delivered by a primary care provider in 8 visits (10–15 minutes each); (2) lifestyle-modification counseling alone delivered in 30 group sessions; (3) sibutramine plus 30 group sessions of lifestyle modification (combined therapy); or (4) sibutramine plus brief lifestyle modification delivered by a primary care provider in 8 visits. All participants were prescribed a 1200–1500 kcal/day diet and the same exercise regimen.

What was found

At 1 year, mean (±SD) weight loss differed significantly across groups (P < 0.001): - Combined therapy: 12.1 ± 9.8 kg - Sibutramine alone: 5.0 ± 7.4 kg - Lifestyle modification alone: 6.7 ± 7.9 kg - Sibutramine plus brief therapy: 7.5 ± 8.0 kg In the combined-therapy group, subjects who frequently recorded food intake lost significantly more weight than infrequent recorders (18.1 ± 9.8 kg vs. 7.7 ± 7.5 kg, P = 0.04).

Why it matters

Pharmacotherapy for obesity is frequently prescribed with little to no behavioral support. This trial shows that combining medication with structured group lifestyle modification yields substantially greater weight loss than medication or lifestyle intervention alone.

Limits

The abstract does not provide dropout rates, adverse event data, cardiovascular outcomes, or post-treatment maintenance data beyond 1 year. The high-intensity counseling regimen (30 group sessions) may be difficult to replicate in standard primary care settings.

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