Abstract
BACKGROUND: The precise mechanisms underlying the health benefits of time-restricted eating (TRE) are unclear, particularly in adolescents. OBJECTIVES: This secondary analysis examines the impact of 8-h TRE on energy intake, dietary composition and quality in adolescents with obesity, using data from a 12-week randomized, controlled pilot trial. METHODS: Participants (14-18 years with BMI >95th percentile) were assigned to either 8-h TRE with real-time or blinded continuous glucose monitoring or a control group with a 12+ h eating window. Dietary intake was analysed using the Nutrient Data System Recall 24-h Dietary Recall and the Healthy Eating Index (HEI-2020) for assessing diet quality. RESULTS: The study included 44 participants (32 TRE, 12 control), predominantly female and Hispanic/Latino. The TRE group showed a significant reduction in mean energy intake (-441 kcal/day), carbohydrates (-65 g/day), added sugar (-19 g/day) and fat (-19 g/day), while the control group had a similar reduction in energy intake (-437 kcal/day) and carbohydrates (-63 g/day), but no significant changes in added sugar or fat. The percent energy intake from protein increased more in the TRE group compared to the control. The TRE group experienced a significant improvement in diet quality, with a 6.3-point increase in HEI-2020 score; however, between-group comparisons were not statistically significant. CONCLUSION: There were no significant differences between the TRE and control groups in energy intake, dietary composition or quality. Future research with larger sample sizes is needed to further evaluate the potential impact of TRE on dietary behaviours.