Over 50% of South African adult women and 30% of adult men are either overweight or obese, and nearly half of all adults are insufficiently active, with major increases in obesity-associated healthcare expenditures since 1980, a high proportion of which are paid by private health insurance. In this paper, we describe the Vitality programme, an incentivized health promotion programme from South Africa's largest private health insurer, Discovery Health, with over 2.5 million beneficiaries. Wellness activities of the programme include health risk assessments, subsidized gym memberships and smoking cessation or weight loss programmes with many incentives, including cash back on purchases of healthy foods. This incentive-based programme has shown a significant relationship between levels of engagement in wellness activities, in particular increasing participation in fitness-related activities, with lower healthcare expenditure and an increase in the overall ratio of healthy foods to total food purchases. This programme demonstrates that incentives may reduce the barriers for entry into care, increase preventive screening and increase engagement in healthy behaviours for prevention and management of obesity. This ‘carrots versus sticks’ approach may have implications for public health policy even in lower- and middle-income settings and underserved communities.