Case Study

Healthier Food Purchases by Pre-Commitment 2

In Collaboration With:

Discovery Health, the largest private health insurer in South Africa, offers a rewards-based program (Vitality) to its members for a fee. Participants earn points for healthy behaviors like exercise, purchasing healthy foods at the grocery store, and routine biometric screenings (the measurement of physical characteristics such as height, weight, body mass index, blood pressure, blood cholesterol, blood glucose, and aerobic fitness tests). In turn, these points earn status that can be used for discounts―anywhere from 5-25% off of groceries (only healthy items), gym discounts, airline tickets, and movie passes.


People often have difficulty engaging in healthy behaviors on their own and look to programs for help. How should these programs be designed to ensure that their members get the most out of them?


The Center for Advanced Hindsight was interested in how we could use pre-commitment incentives to encourage people to make healthier food purchases. We worked with Discovery Health’s Vitality program to maximize the power of incentives to change health behaviors. Participants in Vitality's rewards-based program were offered the opportunity to pre-commit to increasing their healthy food purchases at the grocery store by 5% each month, or else lose their pre-existing healthy food cash-back bonus.


In total, 36% of eligible households chose to pre-commit to the program, increasing their healthy food purchases by 3.5% in each of the study’s six months.

Value for Sponsor

Discovery Health is armed with the knowledge that offering commitment devices may be an effective tool to help people activate and maintain self-control when making food purchases.