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New research published by The Lancet shows that adults referred to a commercial weight loss programme (Weight Watchers) lose around twice as much weight as people receiving standard care over 12 months. The study is led by Dr Susan Jebb, UK Medical Research Council (MRC) Human Nutrition Research unit, Cambridge, UK, and colleagues.

The trial assessed 772 overweight and obese adults in Australia, Germany, and the UK. Patients were randomly assigned to receive either 12 months of standard care as usually offered by the primary care team or referred to and given a 12-month free membership for a Weight Watchers group in their locality.

Of the 377 participants assigned to the commercial programme, 230 (61%) completed the 12-month assessment; the remainder (395) were assigned to standard care, of whom 214 (54%) completed the 12-month assessment. In all analyses, participants in the commercial programme group lost around twice as much weight as did those in the standard care group. The mean weight change at 12 months was –5.1 kg for those in the commercial programme versus –2∙2 kg for those receiving standard care (for all participants in each group). For those who completed the 12 months, mean weight loss was 6.7kg in the commercial programme versus 3.3kg is the standard care group). Participants randomised to Weight Watchers were also more than 3 times as likely to lose at least 5% of their bodyweight compared with those receiving standard care.

The authors say: “The similar weight losses achieved in Australia, Germany, and the UK implies that this commercial programme, in partnership with primary care providers, is a robust intervention that is generalisable to other economically developed countries.”

They add: “The greater weight loss in participants assigned to the commercial programme was accompanied by greater reductions in waist circumference and fat mass than in participants assigned to standard care, which would be expected to lead to a reduction in the risk for type 2 diabetes and cardiovascular disease…This kind of research is important so that we can identify clinically effective interventions to treat obesity”

They conclude: “Data from our study suggest that referral by a primary health-care professional to a commercial weight loss programme that provides regular weighing, advice about diet and physical activity, motivation, and group support can offer a clinically useful early intervention for weight management in overweight and obese people that can be delivered at large scale (panel). Further research is needed to examine long-term weight loss maintenance, together with a formal analysis of cost-effectiveness.”

In a linked comment, Dr Kate Jolly and Dr Paul Aveyard, School of Health and Population Sciences, University of Birmingham, UK, say: “Cost-effectiveness is likely to be a key factor as to whether such commercial programmes become part of publicly funded health care, but the low cost of these programmes (at present about £50–60 for 12 weeks) makes the case for incorporation intuitively appealing.”