Systematic reviews of interventions to treat and prevent obesity

Abstract

Aim: To systematically review lifestyle interventions to treat and prevent obesity in adults, children and vulnerable subgroups. Methods: Cochrane methodology and a "best available evidence‟ approach were adopted to produce a series of published systematic reviews. Results: Adults: diets alone and with exercise and/or behaviour therapy compared with control significantly reduced weight for up to three years (weighted mean difference weight change 4 to 13 kg at one year) and prevented weight gain for up to seven years. Exercise as an adjunct to diet and also meal replacements may be effective in the long-term maintenance of weight loss. 600 kcal/day deficit or low-fat diet; diet and exercise with/without behaviour therapy; significantly reduced the risk of hypertension, type 2 diabetes and metabolic syndrome compared with control. School-children: 39% of school-based interventions significantly improved mean body-mass index compared with control. Combined diet and physical activity interventions were most effective. It is unclear what elements of interventions are consistently effective in preventing excessive weight gain. There can be significant prevention of weight gain in children from interventions not conceptualized as obesity prevention interventions. Vulnerable subgroups: lifestyle interventions can prevent excessive weight gain in pregnancy and help weight-concerned women stop smoking. Diet and exercise can reduce weight in postmenopausal women. There is insufficient evidence to inform how interventions need to be modified to meet the needs of pre-school children or ethnic minority groups within the UK. Conclusions: This evidence underpins national guidance, informs government policy and influences clinical practice. Population-wide recommendations may be effective in preventing a population increase in prevalence of obesity only as part of a government strategy that includes environmental change and is coupled with targeted interventions to reduce the prevalence of obesity caused at least in part by social inequalities.