Introduction

Although interest in and funding to treat obesity have increased,1 its prevalence has not yet decreased. In this review I summarise the evidence behind interventions to treat or prevent obesity in adults, children, and communities; discuss the strengths and weaknesses of current research; and recommend a direction for future treatment and research.

Methods

I systematically searched the literature during January 2004 and synthesised the results of systematic reviews of obesity treatment and prevention. The methods and results are fully described in the monograph “What works for obesity?” (www.unitedhealthfoundation.org/obesity.pdf).

What has been studied?

Studies of lifestyle interventions or a combination of diet and exercise were most common.2 A few treatment programmes involved simple interventions (such as giving brief advice to decrease fat intake), but most did not. Most addressed both diet and physical activity and often had an educational component—behavioural therapy, incentives for attendance and weight loss, or help from family members and health professionals.2 In general, they were time and labour intensive—and therefore probably expensive, although costs were not reported.

Most of the research focused on adults and on individual treatment in a clinical setting.3 Despite the need to address eating and activity habits in early life, research about prevention and treatment of childhood obesity was meagre.4 5

Few studies evaluated the effectiveness of environmental or policy initiatives. Some referred to changes made in the participants' environment, but these were not described in detail and their impact was not analysed separately from that of the main treatment.2 None of the systematic reviews of environmental interventions reported in the literature assessed weight measures as outcome variables.6

Do any treatments work?

Even “effective”dietary and exercise treatments for adult obesity produced modest weight loss (about 3-5 kg) compared with no treatment or usual care.2 3 7 Weight loss drugs such as sibutramine and …