According to Channel 4 documentary series Dispatches, the Health Service has spent the equivalent of £800,000 a year on courses for overweight people since Weight Watchers referrals were approved by health watchdog NICE in 2007.
Two-thirds of Primary Care Trusts now offer the slimming classes as part of their anti-obesity drive, with an estimated 30,000 patients referred each year.
It would seem that it is money well spent though, with a number of recent studies showing that Weight Watchers is highly effective for those who want to lose weight.
In December, a study conducted by the NHS revealed that Weight Watchers attendees lost an average of three pounds more than those who joined other slimming clubs, and after analysis, the study's authors concluded that 81 per cent of Weight Watchers members were more likely to shed five per cent of their weight.
However, the Dispatches programme raises concerns as to the feasibility of some studies.
Claire Friedemann, from the centre of evidence-based medicine at the University of Oxford, analysed ten studies claiming the effectiveness of Weight Watchers... and found that eight of thos had been paid for by the firm itself.
She told Dispatches: "The danger with companies funding their own research is that they may only publish results which are positive for them."
Ms Friedemann said her analysis showed that while many members lost weight within the first three months, some put the pounds back on again after five years.
What do you think? With nearly a quarter of British adults now classified as obese, is NHS spending on Weight Watchers justified? Leave your comments below...