Giving people a monetary incentive to achieve weight loss goals doubles the pounds they lose, according to a new study.
Researchers tracked the weight loss of 668 morbidly obese adults in New York City and Los Angeles over a six-month period. The goal was for participants to lose 10 pounds.
The study, published in JAMA Internal Medicine, found that two thirds of participants achieved the goal when they were offered money as a reward, but those who weren’t lost half the amount of weight.
The average weight of participants before the study was 218 pounds with a BMI, or body mass index, of 38, putting them in the morbidly obese range. People in the study were between the ages of 18 to 70 and came from low-income households that had an average income of less than $40,000 a year. The majority — 80% — were women. The study was conducted from Nov. 2017 to May 2021.
Researchers split the participants into three groups, tasked them with losing 5% of their body weight, and assigned incentives randomly. These included: goal-directed incentives, outcome-based incentives, and a resources-only group. All participants were enrolled in a program to help them lose weight.
Each group were given different tools and rewards to help them drop the pounds but only two of the three groups were offered monetary incentives.
The resources-only group participants only used the weight-loss program. The other two groups were given varying financial incentives. The outcome-based incentives group was given self-monitoring tools — a digital scale, food journal and a physical activity monitor — health education, and monthly check ins. The goal-directed group was given weight-loss tools. Both could earn up to $750 by achieving mini-goals.
Participants received $150 for registering and attending at least half of the weekly weight management program sessions for one month, and received $60 monthly if they continued to attend at least half the weekly program sessions.
Participants received up to $30 per month for using their food journal at least five days a week and recording their body weight at least three days per week in the first six months.
They also wore fitness trackers, receiving up to $20 per month if they achieved 75 minutes of physical activity per week, which increased to 150 minutes from month four to month six.
The average amount earned in the goal-directed group was $440.44 with a median weight loss of 9.8 pounds. In the outcome-based group, they earned an average of $303.56 and lost an average of 10.6 pounds.
Those in the group with no financial incentives lost 4.9 pounds during the study period.
Around 61 participants dropped out of the study within the first six months for the goal-based group, with 51 dropping out in the incentive group and 54 in the no cash incentives group.
The study’s senior investigator, Melanie Jay, MD from NYU Langone Health says further research is needed but it offers evidence that incentives can make short-term improvements.
“Our study provides firm evidence that offering incentives, especially cash rewards, even if only for six months, helps people of limited means struggling with obesity to lose weight,” Jay said in a press release. “However, any kind of incentive to lose weight can work, even if it is just offering the tools to help do so.”