Effects of anti-obesity drugs, diet, and exercise on weight-loss maintenance after a very-low-calorie diet or low-calorie diet: a systematic review and meta-analysis of randomized controlled trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 24172297 · doi:10.3945/ajcn.113.070052
What was done
A systematic review and random-effects meta-analysis of randomized controlled trials (MEDLINE, Cochrane Controlled Trial Register, EMBASE from 1981 to 2013) assessing strategies to maintain weight loss after an initial very-low-calorie or low-calorie diet (<1000 kcal/d). Twenty studies with 27 intervention arms and 3,017 participants were included across six categories: anti-obesity drugs (3 arms; n = 658), meal replacements (4 arms; n = 322), high-protein diets (6 arms; n = 865), dietary supplements (6 arms; n = 261), other diets (3 arms; n = 564), and exercise (5 arms; n = 347).
What was found
Initial weight change during the diet phase was -12.3 kg (median duration: 8 weeks). For maintenance compared with controls, significant improvements were seen with meal replacements (3.9 kg; 95% CI: 2.8, 5.0 kg; median duration: 12 months), anti-obesity drugs (3.5 kg; 95% CI: 1.5, 5.5 kg; median duration: 18 months), and high-protein diets (1.5 kg; 95% CI: 0.8, 2.1 kg; median duration: 5 months). Exercise (0.8 kg; 95% CI: -1.2, 2.8 kg; median duration: 10 months) and dietary supplements (0.0 kg; 95% CI: -1.4, 1.4 kg; median duration: 3 months) showed no statistically significant difference versus controls.
Why it matters
Weight regain is common after rapid weight loss; this synthesis indicates that structured dietary strategies (high protein, meal replacements) and pharmacotherapy offer meaningful maintenance benefits, whereas exercise or dietary supplements alone yielded no statistically detectable advantage in these trials.
Limits
Durations varied markedly across interventions (median 3 months for supplements vs. 18 months for drugs), limiting direct comparisons. Several intervention categories had small sample sizes and few trials (e.g., only 3 drug arms and 4 meal-replacement arms). Specific drug types, exercise protocols, participant adherence, and adverse events were not detailed in the abstract.