Abstract
IMPORTANCE: It remains largely unknown whether the timing of the eating window during time-restricted eating (TRE) affects sleep, mood, and quality of life differently. OBJECTIVE: To investigate whether 3 TRE schedules-an 8-hour eating window in the early part of the day, the late part of the day, or selected by the participant-combined with usual care (UC; a Mediterranean diet education program) were associated with changes in sleep, mood, and quality of life compared with UC alone in adults with overweight or obesity over a 12-week intervention. DESIGN, SETTING, AND PARTICIPANTS: This was a prespecified secondary analysis of a parallel-group randomized clinical trial conducted from April 11, 2022, to March 6, 2023, in Granada (southern Spain) and Pamplona (northern Spain). Eligible participants were men and women aged 30 to 60 years with overweight or obesity. Data analyses for the current study were performed between March 14, 2024, and December 5, 2024. INTERVENTION: Participants in the UC group maintained their usual eating window (≥12 hours daily) and received an educational program based on the Mediterranean diet. Participants in the early TRE group had an 8-hour eating window starting before 10 am and the late TRE group, after 1 pm; self-selected TRE participants chose their own 8-hour window. All TRE participants also received the UC educational program. Group allocation was 1:1:1:1. MAIN OUTCOMES AND MEASURES: Changes in sleep were objectively assessed using accelerometry for 2 weeks before the intervention and during the final 2 weeks of the intervention. Changes in mood dimensions-depression, anxiety, and stress-and quality of life were assessed before and after the 12-week intervention using self-administered questionnaires. RESULTS: A total of 197 participants (98 women [49.7%]; mean [SD] age, 46.1 [8.4] years; mean [SD] body mass index, 32.8 [3.2], calculated as weight in kilograms divided by height in meters squared) were randomized to UC (n = 49), early TRE (n = 49), late TRE (n = 52), and self-selected TRE (n = 47). No significant differences were observed between the early TRE and UC groups for sleep (eg, mean difference in total sleep time, 0.2 [95% CI, -0.2 to 0.6] hours), mood (eg, mean difference in Beck Depression Inventory Fast Screen score, 0.2 [95% CI, -1.0 to 1.3] points; mean difference in state anxiety score on the State-Trait Anxiety Inventory, -1.2 [95% CI, -6.4 to 4.1] points; mean difference in Perceived Stress Scale score, 2.1 [95% CI, -1.8 to 5.9] points), and quality of life (eg, mean difference in general health score on the Rand 36-Item Short Form Health Survey, 3.3 [95% CI, -4.4 to 10.9] points). Results were also nonsignificant for the late TRE and self-selected TRE groups compared with the UC group as well as between the TRE groups. CONCLUSIONS AND RELEVANCE: In this secondary analysis of a randomized clinical trial of 3 different TRE schedules, incorporating TRE into a UC intervention, regardless of the eating window timing, was not associated with significant changes in sleep, mood, or quality of life compared with UC alone in adults with overweight or obesity. The findings suggest TRE may be a viable nutritional weight management strategy without adverse effects on sleep, mood, or quality of life. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05310721.