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

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.

Conditions

• Health
• Energy Intake
• Eating Behaviors
• Appetite

Interventions

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.

Sponsors & Collaborators

• Technical University of Munich

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

30 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-04-01

Primary Completion

2025-11-30

Completion

2025-12-15

Countries

• Germany

Study Locations