Robert Carter is concerned he may have over-gambled
A new method of losing weight by betting on your own success is gaining popularity in the UK.
Bet dieters join a website and make a commitment to lose a certain amount of weight over a defined period of time.
Then, if they fail to meet their targets, money is withdrawn from their account and paid to a charity of their choice.
The scheme started in the US, but already has more than 1,000 followers in the UK.
Not only are people who sign up hit in the wallet if they fail, their friends can get to hear about it via a group e-mail.
In the US the scheme is said to be achieving success rates of up to 85%.
All weight loss must be verified by a referee.
The founders say a particularly effective way to encourage people to lose weight is to get them to nominate a charity with whose views they disagree to receive money should they fail.
Jordan Goldberg, co-founder of the StickK bet dieting website, said: "The anti-charity aspect is where we take your money and we send it to an organisation that you oppose should you fail.
"We chose some highly contentious issues, for instance global warming, abortion and gay marriage.
"The idea is you choose an organisation whose views are contrary to your own as an added incentive to stay motivated to succeed."
Robert Carter, an investment analyst from Dorset who has been bet dieting for over a month, says his experience has been mixed.
He said: "I passed the first week, I lost my pound and half. I only lost a pound in the second week and so I failed, so I have given my £3.60 to the charities.
"I think I will lose the weight, it is certainly an incentive. I'm not sure I if have over-gambled, I might end up giving them £3.60 every week, and falling slightly behind.
"But I think it is certainly a good project."
Doctors remain to be convinced by the long-term effect of the schemes.
Professor Richard Ashcroft, of the Centre for the Study of Incentives in Health, said: "When somebody is in the middle of an incentive scheme they can be quite effective.
"People can be quite good at their weight loss programmes, eating less or taking more exercise.
"The problem is once the incentive scheme has finished we don't know if they carry on being successful after that - we don't know if people manage to stay with the weight loss or exercise regime once the incentive is taken away."