Conclusion
In the Supreme Nudge trial, supermarket flyers were the most cost-effective in recruiting participants of all paid strategies. Mailings to home addresses recruited the most participants but were very costly. Conducting at-home cardiometabolic measurements was feasible with relatively high completion rates. These insights are valuable for future research projects that aim to recruit a diverse study population and to study cardiometabolic risk markers in, for example, geographically large and widespread groups or when face to face contact is not possible.