Which weight-loss programmes are as effective as Weight Watchers^®?

Background Three randomised controlled trials have provided strong evidence that Weight Watchers^® is an effective weight-loss programme but there is insufficient evidence to determine whether three other weight-loss programmes are also effective.

Aim To examine whether other group-based weight-loss programmes were not inferior to Weight Watchers.

Design and setting A prospective cohort study using a non-inferiority analysis of 3290 adults referred through primary care.

Method Participants who met the eligibility criteria for primary care obesity management treatment chose a free programme (Weight Watchers, Rosemary Conley Diet and Fitness Clubs, Slimming World or a NHS group programme) lasting 3 months; they were weighed at 3 months (programme end) and self-reported their weight at 12 months.

Results At 3 months, weight loss achieved through Rosemary Conley and Slimming World was not inferior to Weight Watchers. The NHS group programme was inferior. At 12 months Slimming World and Rosemary Conley were not inferior to Weight Watchers, although participants using Slimming World lost significantly more weight than those using Weight Watchers. Data on the NHS group programme were inconclusive.

Conclusion In the short term all commercial weight-loss programmes appear to result in similar weight loss but the NHS alternative appears to produce less weight loss. At 12 months Slimming World led to greater weight loss but the differences between commercial programmes was small and of minor clinical importance.