Improving diet is a key strategy to prevent obesity and improve health. South Africa's largest insurer, Discovery, in partnership with Vitality Group, decided to offer 10% and 25% cash-back rebates on fruits, vegetables, non-fat dairy and other healthful foods to members of its health promotion program. To get the 25% rebate, members had to fill out a questionnaire.
Researchers supported by the Population Dynamics Branch looked at spending on these foods for more than 170,000 households. The researchers found that household spending on healthy foods increased 9.3% (calculated as a ratio of spending on healthy food to total food spending) with the 25% rebate. A 10% rebate nudged people to buy healthier stuff, too, just a little less—resulting in a 6% increase (PMID: 23683973).