Twenty-five randomised controlled trials (n=3,600) published in 30 articles and rated as fair or high quality were included in the analysis.
Behavioural interventions showed short-term benefits in terms of BMI. Comprehensive medium-to-high-intensity behavioural interventions showed the most improvements (SMD -1.01, 95% CI -1.24 to -0.78; three studies, n=425). Comprehensive very low intensity interventions showed moderate but statistically significant benefit (SMD -0.39, 95% CI -0.66 to -0.11; three studies, n=208). Comprehensive low intensity or focused interventions did not show any improvement. Data on maintenance phase of behavioural interventions were limited, but available evidence suggested improvement of these interventions could be maintained more than 12 months after the end of the intervention.
Two studies that assessed medication (sibutramine or orlistat) combined with behavioural interventions demonstrated small-to-moderate short-term weight loss. There was a mean BMI reduction of 2.9kg/m2 for sibutramine compared with 0.3kg/m2 in the control group (one study, n=498) and 0.55kg/m2 versus 0.3kg/m2 for orlistat versus control (one study, n=539). No study followed weight changes after medication had stopped.
Adverse events were reported only for the pharmacological intervention. No serious events were reported.
Sensitivity analysis did not change the results.