A 24-week parallel-arm randomized controlled pilot trial — the DiAL Health study — is enrolling 90 healthy adults (BMI 22–29.9, ages 22–45) across five arms: non-intervention control, traditional or adaptive time-restricted eating (8-hour window), and traditional or adaptive 25% calorie restriction. The adaptive arms leverage just-in-time adaptive interventions (JITAIs) via mobile health technology to deliver real-time, personalized adherence prompts. Primary outcomes focus on feasibility; secondary outcomes include the Klemera-Doubal biological age composite and metabolic syndrome score as health-span proxies.
Adherence collapse is the silent killer of dietary intervention research — both calorie restriction and time-restricted eating have robust short-term evidence but notoriously poor long-term compliance in free-living populations. The JITAI framework, borrowed from behavioral health technology, is a genuinely novel mechanism to address this gap, moving dietary support from scheduled clinic visits to context-sensitive, behavior-triggered nudges. The Klemera-Doubal biological age score as a secondary endpoint is an astute choice, as it integrates multiple physiological parameters into a single aging metric with meaningful predictive validity. That said, this is a protocol paper describing a pilot trial — no efficacy data exist yet, the sample is young and non-obese, limiting generalizability, and the 24-week window may be insufficient to detect meaningful biological age shifts. Confirmatory at this stage, but the JITAI-longevity integration is genuinely worth watching.