Abstract Body: Background: Time-restricted eating (TRE) interventions demonstrate heterogeneity in the eating window duration. The purpose of this study was to examine the feasibility, acceptability, and adherence of two TRE strategies (10-hr vs 6-hr).

Methods: Eligible participants had ≥5% non-surgical weight loss (self-reported) within the last 3 months and BMI: 20.5-45 kg/m²; were 25-65 y; had an eating window >12 h/day and completed a 4-week (wk) run-in to determine weight stability and eating window length. Participants were randomized to a self-selected 10 h (TRE10) or 6 h (TRE6) eating window for 12 weeks. Both arms received 8 educational and behavioral counseling sessions via videoconferencing (WebEx). Participants in both arms were asked to enter all eating occasions (foods and caloric beverages) into a smartphone application (MyCircadianClock) to assess eating window adherence. Feasibility and acceptability were determined based on retention and participant experience using an investigator-developed questionnaire (TRE Experience Questionnaire [TRE-EQ]). Mann-Whitney U test was used to compare data between the two arms. Baseline data are reported as means and standard deviations.

Results: Participants were 46±10 y, 55% White, 36% African American, 27% Hispanic, and mostly female (73%) with a BMI of 30.1±6.2 kg/m². The average self-reported weight loss before randomization was 9.2%±4.3%. A total of 29 participants were enrolled and 22 (n=11/arm) were randomized. Retention was 90%, with only two participants dropping out during the study, one from each arm. Additionally, TRE-EQ data indicates the participants in the TRE10 agreed to more statements around less hunger (p=0.09), their assigned program was easy to follow (p=0.02), their assigned program fits their daily routine (p=0.08) and they were adherent to their eating window (p=0.03) compared to participants in the TRE6 arm. Data from the mCC app suggests no difference between TRE10 and TRE6 regarding eating window adherence (p=0.41). There was a trend for the TRE10 arm to log fewer days with at least one eating occasion outside the designated eating window than the TRE6 arm (p=0.06).

Conclusions: A 12-week 10-hr TRE intervention is more feasible and acceptable for adults with recent weight loss compared to a 6-hr TRE intervention.