A new study presented at the European Congress on Obesity (ECO) in Venice, Italy (12-15 May), and published simultaneously in JAMA, has concluded that text messages with financial incentives can help men who are living with obesity lose weight and could be a valuable alternative to traditional weight management programs.

Men who were offered cash for hitting weight loss targets lost more weight than those not given a financial incentive, the UK-based Game of Stones trial found.

Around 26% of men in the UK are living with obesity. However, men are under-represented in weight loss trials and less likely than women to attend traditional weight loss groups—and this is particularly the case for men from lower socioeconomic groups.

Professor Pat Hoddinott, of the Nursing, Midwifery and Allied Health Professions Research Unit at the University of Stirling and team wanted to explore whether the combination of text messages and cash incentives would help men, including those from lower socioeconomic groups, lose weight.

She explains, "One of the most effective incentive strategies in the literature uses 'deposit contracts,' where people deposit their own money and lose it if they do not meet weight loss goals. This is informed by behavioral 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."

A text message-based program, meanwhile, costs less and is less labor-intensive than a traditional weight loss program.

"Men who were living with obesity helped design the structure of the incentives and helped us write the text messages," says Professor Hoddinott.

Professor Hoddinott and colleagues ran the 12-month-long randomized Game of Stones clinical trial in Belfast, Bristol and Glasgow. It involved 585 men living with obesity (average age 50.7 years, average weight 118.5kg/18st 9lb, average BMI 37.7kg/m²) who were randomly assigned to one of three groups: text messaging with financial incentives, text messaging alone or waiting list (control).

Those assigned to the text messaging with financial incentives group (n=196) received daily text messages, including motivational messages, tips from other men on how they changed their eating habits and lifestyle and links to evidence-based websites. They were also given access to a study website with evidence-based information on weight management, information about local weight management services and an online tracker to monitor their weight change.

They were also told that £400 had been placed in an account for them and would be transferred to them at the end of the trial. However, some of the money would be lost each time they failed to meet one of three weight-loss targets. £50 would be taken away if they didn't lose 5% of their body weight after 3 months, £150 taken away if they didn't lose 10% of their weight after 6 months and £200 taken away if they hadn't maintained the 10% weight loss after a year.

The men assigned to the text-messaging alone group (n=194) received the same text messages and could use all the features on the study website but were not offered financial incentives for weight loss.

Those in the control group (n=195) only had access to the evidence-based weight management information.

A total of 426 of the 585 men logged their weight after 12 months.

The men in the text-messaging-with-financial-incentives group lost the most weight. They lost 4.8% of their body weight (5.7kg/13lb) over 12 months, on average; this compares to 2.7% (3kg/6.6lb) for the text-messaging-only group and 1.3% (1.5kg/3.3lb) for the control group.

Further analysis revealed that weight loss in the text-messaging-with-financial-incentives group was statistically significant compared to the control group. In contrast, weight loss in the text-messaging-alone group did not differ significantly from the control group.

Four men would need to receive text messages with financial incentives for one to achieve weight loss of 5% or more and five would need to take part for one to achieve weight loss of at least 10%, say the researchers.

The men in the text-messaging-with-financial-incentives group received £128 each, on average, with 27 receiving the full £400.

Survey results showed that men in the text-messaging-with-financial-incentives group rated their health as being significantly better at the end of the trial.

Professor Hoddinott adds, "It is also important to note that we were able to recruit men from several populations normally under-represented in weight management trials. Some 39% of the men lived in less affluent areas, 71% reported a long-term health condition, 40% reported two or more long-term conditions and 29% reported that they were living with a disability. In addition, 25% of the men told us they had a doctor-diagnosed mental health condition and a further 24% reported low mental health scores."

The researchers conclude that text messages with financial incentives are effective at encouraging weight loss in men living with obesity and could potentially be delivered at scale.

They hope the strategy will be adopted by the NHS and say that given the huge cost of overweight and obesity to the NHS, the use of financial incentives could potentially pay for itself in the long term. A health economic evaluation is underway.

Professor Hoddinott adds, "We reached an underserved group of men who seldom take part in health promotion activities. Weight management programs are traditionally intensive, often with a weigh-in every week or two. In Game of Stones, there are just four brief ten-minute weigh-ins over a year. No intervention is delivered by the staff at the weigh-ins, so minimal staff training is required. No referral is needed to join.

"Men and NHS staff really valued this low burden approach and it has the potential to address health inequalities. It was a win-win for all."

Provided by European Association for the Study of Obesity