Health and cosmetic factors are two of the best motivators for weight loss, according to one GP.
Dr David Haslam, who also chairs the National Obesity Forum, opted for the two factors over money.
"If money is a motivation, and then they stop getting paid and the scheme finishes, their motivation has gone, so to me, it is not as sustainable a motivation as wanting to be healthier or to live longer," said Dr Haslam.
His comments followed a trial conducted by NHS Eastern and Coastal Kent, which gave patients financial rewards for losing weight.
The project had varied results. Two-thirds of the patients who began the scheme in January last year failed to reach their target weight.
However, of those who remained in the trial, the average weight loss was a significant 25 pounds each.
Health is a major concern in the UK where statistics from the NHS found that almost a quarter of all adults in England are classified as obese.
Independent advice on private healthcare