In a randomized clinical trial, adding financial rewards to a meal replacement program significantly boosted weight loss and fat reduction in severely obese teens compared to meal replacements alone.
The 52-week study, published in JAMA Pediatrics, included 126 adolescents aged 13-17 with severe obesity and a mean BMI of 40.6 at baseline. One group received proportioned, calorie-controlled meals, while the other group received the same meals plus $20 gift cards for every 0.5% decrease in body weight from baseline, with payments made at 2, 4, 6, 8, 10, and 12 months. Participants were reimbursed up to $700 for completing study visits, regardless of group assignment.
At the end of the trial, which had a 70.6% retention rate, the group receiving financial incentives achieved a 5.9% greater reduction in BMI and lost 4.8 kg more total body fat, as measured by dual-energy x-ray absorptiometry, than the meal replacement-only group.
The monetary rewards did not lead to an increase in unhealthy behaviors like laxative abuse or self-induced vomiting. The researchers believe the incentives may have motivated the teens to stick with the meal plan more consistently, resulting in more substantial and long-lasting weight loss.
A cost-effectiveness analysis, using a commonly accepted willingness-to-pay threshold of $100,000 per quality-adjusted life-year, revealed that despite the added expense of the rewards, the incentive program was still cost-effective compared to meal replacements alone. One-way sensitivity analyses showed that the financial incentive program remained cost-effective in most scenarios, except when BMI reduction did not improve quality of life. Probabilistic sensitivity analyses demonstrated cost-effectiveness in 74% of 1,000 iterations.
The study also assessed cardiometabolic risk factors, heart rate variability, arterial stiffness and quality of life. However, no significant differences were observed between the groups in these measures.
There was one serious adverse event (hospitalization related to asthma) in the financial incentive group and three serious adverse events (hospitalizations for suicide attempt, overdose, and pneumonia) in the meal replacement-only group, all deemed unrelated to study participation.
While the study had limitations, such as a lack of adherence data and higher-than-anticipated dropout rates possibly due to the COVID-19 pandemic, the findings suggest financial incentives could be a promising addition to weight management interventions for severely obese adolescents.
Conflicts of interest can be found in the full study.
