Early Time-Restricted Feeding Reduces Appetite and Increases Fat Oxidation But Does Not Affect Energy Expenditure in...

Area of Science:

• Metabolism and Endocrinology
• Chronobiology
• Nutritional Science

Background:

• Circadian rhythms influence metabolic processes.
• Early time-restricted feeding (eTRF) shows promise for weight management.
• The precise mechanisms by which eTRF affects energy metabolism are not fully understood.

Purpose of the Study:

• To investigate the impact of eTRF on 24-hour energy metabolism.
• To determine if eTRF-induced weight loss benefits are mediated by energy expenditure or appetite changes.
• To conduct the first randomized trial matching food intake and meal frequency.

Main Methods:

• Eleven overweight adults participated in a randomized crossover trial.
• Participants practiced eTRF (8 am-2 pm) and a control eating schedule (8 am-8 pm) for 4 days each.
• Whole-room indirect calorimetry assessed 24-hour energy expenditure and substrate oxidation, alongside appetite and hormonal measurements.

Main Results:

• eTRF did not significantly alter 24-hour energy expenditure.
• eTRF led to a significant decrease in ghrelin levels and a more even hunger profile.
• Metabolic flexibility was enhanced, and the nonprotein respiratory quotient decreased with eTRF.

Conclusions:

• Meal timing, specifically eTRF, primarily facilitates weight loss by reducing appetite.
• eTRF may contribute to fat loss by increasing fat oxidation.
• Aligning eating patterns with circadian rhythms offers a novel approach to weight management.