Tens of thousands of fat and overweight people are attending private slimming clubs at NHS expense because it is said to be cheaper than other treatments.
Buying vouchers from commercial weight-loss organisations is reportedly a third less expensive than alternatives such as slimming drugs and "tummy tuck" operations.
Natalie Field, associate director of public health at Bristol Primary Care Trust, said: "Although we were hesitant about paying a private commercial organisation to provide services, we now have no qualms at all."
All 57 of Bristol`s GP practices are signed up and being encouraged to prescribe a second 12-week course for those who lose 5% of their body weight during the first programme.
These focus on transforming lifestyle with education and claim to be more successful in achieving permanent weight loss than the alternatives.
Said Ms Field: "A small-scale evaluation in 2004 of our scheme suggests that cost per kilogram lost is £16 for patients receiving support through our slimming club programme compared with £50 for drug therapy. We have referred over 2,200 patients to the scheme."
She said attendance is high and initial results suggest that not only do patients lose weight but they don't put it back on.