Cash incentives for losing weight could be the best way to help obese people shed pounds, a trial has found.

Researchers have suggested offering cash incentives to obese people in text messages, as it could be cheaper for the health service than traditional weight management programmes.

It could also help reach people from more deprived areas, they added.

The year-long study – known as Game of Stones – included 585 men from Bristol, Belfast and Glasgow with an average body mass index (BMI) of 37.7, who were split into three groups.

One of the groups was told £400 was being held for each of them in an account and would be transferred over at the end of the trial.

However, money would be taken off the total if they failed to meet weight loss goals.

The group were also sent daily texts that included motivational messages, tips on lifestyle changes, links to information online and access to a study website on weight management with information about local services and an online tracker to monitor changes in weight.

The second group was sent the same messages but with no financial incentive, while the third group was only granted access to the weight management information.

Some 426 men included in the study logged their weight after 12 months.

Those in the financial incentives group lost 4.8% of their body weight on average, compared to 2.7% in the group who were sent the same messages but with no financial incentives and 1.3% in the third group.

Professor Pat Hoddinott, who led the study, said it was inspired by “behavioural economic theory which proposes that people are more motivated by the prospect of losing money than the prospect of gaining money”.

“However, not everyone can afford to deposit their own money, so we designed the Game of Stones trial, which uses an endowment incentive, where the money is put in an account at the start, allowing men on low incomes to join,” Prof Hoddinott added.

“A text message-based programme, meanwhile, costs less and is less labour-intensive than a traditional weight loss programme.

“Men who were living with obesity helped design the structure of the incentives and helped us write the text messages.”

Prof Hoddinott also stressed the study was able to recruit people from areas “normally under-represented in weight management trials”.

Men included in the financial incentives group received £128 each on average at the end of the study, with 27 receiving the full £400.