For decades, doctors have tried to persuade people to quit smoking, exercise more and lose weight. But with mixed success on the exhortation front and facing a rising obesity crisis, British officials are slowly abandoning the health argument and fattening peoples' wallets instead.
The U.K. has tested several programs that pay people to make healthy choices. Although the trials have been small, officials say they have been successful enough to roll them out further. This week, the government announced it will give out five million 50-pound vouchers to families that can be swapped for fruits and vegetables.
"We will be expanding programs that use financial incentives for healthy behavior where the evidence supports it," said a Department of Health spokesman who did not want to be named, in line with government policy.
Some health experts, however, say it's difficult to change people's habits and warn the cash strategies may backfire. Critics also question whether the government's limited health funds could be better used elsewhere.
But the British government is committed to cash pay-outs to try to reverse the obesity epidemic. In several London suburbs, the public transport system ran a pilot study offering kids movie tickets or shopping vouchers if they walked to school. Similar projects are being considered for other parts of the country.
Britain also commissioned the Weight Wins company to test whether paying people to slim down worked. In eastern and coastal Kent, experts found that 400 people in a 2008 trial lost an average of nearly 15 pounds and kept it off for at least one year.
The program paid people up to 425 pounds ($662) if they hit their weight loss target and maintained it for up to 24 months.
"If people drop out, they get nothing," said Winton Rossiter, who designed the program. "And people hate giving up money even more than they like making it."
Similar programs in the U.S. have largely flopped. An American study that examined seven employer-run programs found that the average person lost little more than a pound.
A pilot project in Scotland, meanwhile, offered poor pregnant women food vouchers worth 12.50 pounds ($19.50) a week if they stopped smoking. After one month, nearly 60 percent of them had, and after three months, almost 35 percent had. By last month, health workers had treated more than 500 women, and there are now plans to unveil the program in the rest of Scotland.
Paul Ballard, deputy director of public health in Tayside, where the project started, said it worked because the amount of money made enough of a difference to women in deprived areas.
But some experts say the success of cash-reward programs is limited because people can't stay on them forever.
"To just pay fat people to eat healthy can work for a bit, but in the real world, they're constantly given the opposite message to eat more," said Tim Lang, a professor of food policy at City University in London who has advised the British government.
"If you want to reduce obesity on a societal level, governments will have to make fundamental changes like altering food price systems to make healthy foods cheaper," he said.
Others question whether Britain should be spending money on these programs when health funds are so tight due to government budget cuts.
"I'm not sure cash-based incentives should be rolled out at the expense of things that are already proven to work," said David Haslam, chairman of Britain's National Obesity Forum.
"There are lots of reasons to be healthy, like looking better and living longer and now maybe earning a bit of cash," Haslam said. "But once you spend that cash, what happens to your motivation?"