Long term maintenance of weight loss with non-surgical interventions in obese adults: systematic review and meta-analyses of randomised controlled trials

Abstract

Objective: To systematically review and describe currently available approaches to supporting maintenance of weight loss in obese adults and to assess the evidence for the effectiveness of these interventions.

Design: Systematic review with meta-analysis.

Data sources: Medline, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials.

Study selection: Studies were identified through to January 2014. Randomised trials of interventions to maintain weight loss provided to initially obese adults (aged ≥ 18) after weight loss of ≥ 5% body weight with long term (≥ 12 months) follow-up of weight change (main outcome) were included.

Study appraisal and synthesis: Potential studies were screened independently and in duplicate; study characteristics and outcomes were extracted. Meta-analyses were conducted to estimate the effects of interventions on weight loss maintenance with the inverse variance method and a random effects model. Results are presented as mean differences in weight change, with 95% confidence intervals.

Results: 45 trials involving 7788 individuals were included. Behavioural interventions focusing on both food intake and physical activity resulted in an average difference of -1.56 kg (95% confidence interval -2.27 to -0.86 kg; 25 comparisons, 2949 participants) in weight regain compared with controls at 12 months. Orlistat combined with behavioural interventions resulted in a -1.80 kg (-2.54 to -1.06; eight comparisons, 1738 participants) difference compared with placebo at 12 months. All orlistat studies reported higher frequencies of adverse gastrointestinal events in the experimental compared with placebo control groups. A dose-response relation for orlistat treatment was found, with 120 mg doses three times a day leading to greater weight loss maintenance (-2.34 kg, -3.03 to -1.65) compared with 60 mg and 30 mg three times a day (-0.70 kg, 95% confidence interval -1.92 to 0.52), P=0.02.

Conclusions: Behavioural interventions that deal with both diet and physical activity show small but significant benefits on weight loss maintenance.

Fig 1 Flowchart of systematic process for report identification

Fig 2 Risk of bias graph showing review authors’ judgments about each risk of bias item presented as percentages across all included studies

Fig 3 Mean difference in weight change at 12 months after initial weight loss in behavioural/lifestyle studies. BC=behaviour therapy + post-treatment therapy contact condition; BCA=behaviour therapy + post-treatment therapy contact + aerobic exercise maintenance condition; BCAS=behaviour therapy + post treatment therapy contact + aerobic exercise maintenance + social influence maintenance programme condition; F2F=face to face condition, FIPS=frequent in-person support condition; MIPS=minimal in-person support condition; Int=internet condition; PST=problem solving therapy condition; RPT=relapse prevention training condition; SF=skill focus condition, phone=telephone condition; WF=weight focus condition

Fig 4 Mean difference in weight change at 12 months after initial weight loss in pharmacological intervention studies. O120=orlistat 120 mg 3 times daily; O60=orlistat 60 mg 3 times daily; O30=orlistat 30 mg 3 times daily; OO v OP=comparison between groups who lost weight using orlistat 120 mg and low energy diet for 1 year followed by randomisation to continued orlistat 120 mg treatment or placebo condition; PO v PP=comparison between groups who lost weight using placebo and low energy diet for 1 year followed by randomisation to continued orlistat 120 mg treatment or placebo condition