Digital Personalization and Behavior

• Personalized interventions had a small to moderate effect on health behaviors.
• The degree of personalization and theoretical foundation moderated the effect.
• Programs differ substantially; the average masks those that do not work.

Every message type in Letz has a registered hypothesis and an adherence metric before being considered effective.

Digital interventions for physical activity, diet, and other lifestyle behaviors.

The evidence evaluates full interventions; it does not prove that an isolated message or insight drives change.

• Tong et al., Preventive Medicine, 2021 DOI 10.1016/j.ypmed.2021.106532

• Adaptive support at the right momentContext-tailored digital interventions can be feasible and helpful, but their effect varies and must be measured per person and per decision.
• Tracking is the most effective techniqueSelf-monitoring of diet, weight, and activity is consistently associated with greater weight loss; the behavior change technique taxonomy ranks it among the most effective.
• Building a workout habitIn new gym members, working out at least four times per week for six weeks was the minimum threshold to form a habit; consistency and simplicity predicted habit formation.