Clinical Protocol for the Dietary Approaches to Longevity and Health (DiAL Health) Pilot Trial

Calorie restriction (CR) and time-restricted eating (TRE) consistently improve biomarkers of aging and health span, yet long-term adherence to these dietary strategies remains difficult. Technology-enabled approaches, including just-in-time adaptive interventions (JITAIs), may facilitate greater engagement by delivering personalized support in response to an individual's real-time behavior and circumstances.

The Dietary Approaches to Longevity and Health (DiAL Health) pilot trial is designed to evaluate the feasibility, acceptability, and preliminary efficacy of adaptive (JITAI-supported) compared with traditional implementations of CR and TRE and to identify outcome measures suitable for larger, long-term intervention studies.

This 24-wk, parallel-arm, randomized controlled pilot trial will enroll 90 healthy adults aged 22 to 45 y with a BMI of 22.0 to 29.9 kg/m² into 1 of 5 groups: nonintervention control, traditional or adaptive TRE with an 8-h eating window, and traditional or adaptive CR targeting a 25% reduction in energy intake. Traditional interventions will emphasize in-person counseling, whereas adaptive interventions will be supported by mobile health (mHealth) technology and incorporate remote monitoring via digital tools and JITAI-based feedback to quantify eating behaviors in real time and deliver tailored adherence prompts.

Primary feasibility outcomes include adherence, retention, and participant satisfaction. Secondary outcomes to assess preliminary clinical efficacy include Klemera-Doubal as a composite measure of biological age and the metabolic syndrome score as a marker of health span. Additional measures including patient-reported outcomes and hallmarks of aging will be collected as exploratory outcomes. Effect sizes will be estimated to guide the selection of primary end points for future large-scale trials.

The DiAL Health pilot trial will provide essential data on the comparative feasibility and potential efficacy of adaptive compared with those of traditional dietary strategies, informing the development of scalable interventions aimed at improving health span and delaying biological aging.This trial was registered at clinicaltrials.gov as NCT05549362.