Commercial weight loss programmes are more effective and cheaper than primary care based services led by specially trained staff, finds a study published on bmj.com. Almost a quarter of the population of England are now classified as obese. Good evidence shows that commercial weight management services can be effective, but the effectiveness of obesity management in primary care is still unclear.

So researchers at the University of Birmingham compared the effectiveness of several commercial weight loss programmes of 12 weeks' duration with primary care led programmes and a control group.

A total of 740 obese and overweight men and women took part. Follow-up data were available for 658 (89%) participants at the end of each 12-week programme and 522 (71%) at one year.

The programmes included in the analyses were Weight Watchers; Slimming World; Rosemary Conley; a group-based dietetics（营养学） programme; general practice one to one counselling, pharmacy one to one counselling; or a choice of any of the six programmes.

A control group was provided with 12 vouchers（付款凭单） enabling free entrance to a local leisure (fitness) centre.

All programmes achieved significant weight loss after 12 weeks, with the average weight loss ranging from 4.4 kg (Weight Watchers) to 1.4 kg (general practice provision). The primary care programmes were no better than the control group at 12 weeks.

At one year, statistically significant weight loss occurred in all groups apart from the one to one programmes in general practice and pharmacy settings. However, Weight Watchers was the only programme to achieve significantly greater weight loss than the control group.

All groups showed some increase in physical activity, although the smallest increase was in those allocated to（分配） the general practice programme.

Attendance seemed to be an important factor; the highest attendance rate was in Weight Watchers and the lowest for the primary care programmes. The primary care programmes were also the most costly to provide.

"Our findings suggest that a 12 week group based dedicated programme of weight management can result in clinically useful amounts of weight loss that are sustained at one year," say the authors.

They add: "Commercially provided weight management services are more effective and cheaper than primary care based services led by specially trained staff, which are ineffective."

In an accompanying editorial, nutrition experts Helen Truby and Maxine Bonham at Monash University in Australia say: "Lighten Up shows that there is no simple solution to the obesity epidemic."

They believe that the NHS should be mindful of the level of investment needed to develop its own expert workforce to manage complex obesity, and it can gain much information from commercial companies in how to deliver what consumers want.