NCT06947824

Time-of-Day Effects of Fasted Exercise on Energy Intake

Effects of Fasted Morning vs. Evening Exercise on Post-Exercise Energy Intake

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 35 (actual)
• Sponsor: Technical University of Munich · Academic / Other
• Sex: All
• Age: 18 Years – 30 Years
• Healthy volunteers: Accepted

Summary

This trial's aim is to investigate the time-of-day effects (morning vs. evening) of fasted exercise on acute and 24h post-exercise energy intake. Specifically, we will compare the effects of fasted morning exercise (12h overnight fast) vs. fasted (6h and 12h) evening exercise on total energy intake during a post-exercise ad libitum test meal as well as on 24h (free-living) energy intake. The secondary aim is to assess subjective appetite ratings before, immediately after, and 30 min post-exercise (visual analog scale). Healthy men and women aged 18-30 years will be included.

Detailed description

In a five-way crossover design, participants will complete three fasted and one non-fasted exercise sessions on a treadmill in randomized order on weekdays with one week in between sessions: once in the morning (\~1h after participants' habitual wake-up time) following a 12h overnight fast (12h AMEx), once in the evening (exactly 12h after the 12h AMEx condition) after a 6h fast (6h PMEx), and once in the evening (identical to the 6h PMEx condition) following a 12h fast (12h PMEx). As control conditions, a subsample of participants (n=17) will also complete a fed morning exercise condition (AMEx Fed; identical timing to 12h AMEx) and a fed evening exercise condition (PMEx Fed; identical timing to 12h PMEx), following a small pre-exercise snack (\~10% of individual energy requirements; 30 min before exercise). The standardized meals provided before the fasting period contained 30% of the individual's daily energy requirements and consisted of \~50% carbohydrates, \~30% fat, and \~20% protein.

Conditions

• Health
• Energy Intake
• Eating Behaviors
• Appetite

Interventions

Type	Name	Description
BEHAVIORAL	Fasted Morning Exercise (12h)	A 30-minute exercise session will take place on a treadmill in the morning (7:00, \~1h after participants' habitual wake-up time), after a 12h overnight fast. The session will consist of 30 minutes of steady state cycling at 65% of VO2max, following a 5 min warm-up.
BEHAVIORAL	Fasted Evening Exercise (6h)	A 30-minute exercise session will take place on a treadmill in the evening (19:00, exactly 12 hours after the morning session), after a 6h fasting period. The session will consist of 30 minutes of steady state cycling at 65% of VO2max, following a 5 min warm-up.
BEHAVIORAL	Fasted Evening Exercise (12h)	A 30-minute exercise session will take place on a treadmill in the evening (19:00, exactly 12 hours after the morning session), after a 12h fasting period. The session will consist of 30 minutes of steady state cycling at 65% of VO2max, following a 5 min warm-up.
BEHAVIORAL	Fed Morning Exercise (AMEx Fed)	A 30-minute exercise session will take place on a treadmill in the morning (7:00, \~1h after participants' habitual wake-up time), after consuming a small pre-exercise snack (30 min before exercise). The session will consist of 30 minutes of steady state cycling at 65% of VO2max, following a 5 min warm-up.
BEHAVIORAL	Evening Fed Exercise (PMEx Fed)	A 30-minute exercise session will take place on a treadmill in the evening (19:00, exactly 12 hours after the morning session), after consuming a small pre-exercise snack (30 min before exercise). The session will consist of 30 minutes of steady state cycling at 65% of VO2max, following a 5 min warm-up.

Timeline

• Start date: 2025-04-01
• Primary completion: 2025-11-30
• Completion: 2025-12-15
• First posted: 2025-04-27
• Last updated: 2026-02-06

Locations

1 site across 1 country: Germany