Abstract 14318: The Effect of Time-Restricted Eating on Physical Activity: Results From the Time-Restricted Intake of Meals (Trim) Randomized Trial

Abstract

Introduction: Time-restricted eating (TRE) is a dietary pattern that may promote weight loss by limiting caloric intake, but evidence for its effects on physical activity are limited. Objective: To determine the effect of a TRE pattern compared to a usual eating pattern (UEP) on physical activity. Methods: We examined physical activity data from 41 adults with prediabetes or untreated diabetes (HbA1c 5.7-6.9%) and obesity (BMI 30-50 kg/m 2 ) randomized to consume 80% of their total calories before 1 pm (TRE) or ≥50% of their calories after 5 pm (UEP) with identical macronutrient content. Participants were fitted with a wrist-worn GT9X accelerometer (Actigraph; Pensacola FL) to measure free-living physical activity behaviors for one week at baseline and 12 weeks. Outcomes were mean total activity counts (measure of activity volume and intensity) and time spent active (measure of activity volume) per day. We used linear mixed effects regression models with participant-specific random intercepts to examine the difference in outcomes between the two groups from baseline to 12 weeks; the intervention-by-time interaction was the term of interest (β int ). Results: Thirty-nine adults (mean age 59.5 years; 92% female; 92% African American) completed actigraphy assessments. We observed a significant decrease in all physical activity measures from baseline to 12 weeks in TRE, but not in UEP ( Table ). Total activity counts (p for β int =0.005), but not time spent active (p for β int =0.094) declined significantly in TRE compared to UEP. Conclusion: In this randomized feeding study, TRE was associated with reduced physical activity intensity while overall physical activity volume was unaffected, compared to a UEP. This unexpected compensatory decrease in physical activity intensity may limit the efficacy of TRE for achieving weight loss. Future studies are needed to understand the mechanisms behind this effect, and to optimize TRE interventions to maintain physical activity levels.