Effects of Fasted Morning vs. Evening Exercise on Post-Exercise Energy Intake
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Enrollment
- 35
- Locations
- 2
- Primary Endpoint
- Acute ad-libitum post-exercise energy intake (test meal)
Study Overview
Brief 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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to 30 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •BMI of 18.5.0-30.0 kg/m2
- •weight stability (≤2.5 kg weight change during the past 3 months)
- •ability to exercise at a vigorous intensity for 30 minutes
Exclusion Criteria
- •pregnancy or breastfeeding
- •history of or current eating disorders
- •medical condition or use of medication that could affect appetite or pose any contraindications to exercise
- •As the menstrual cycle can cause fluctuations in food cravings and appetite, women of childbearing age were only eligible if they used hormonal contraceptives. To ensure constant exposure to exogenous estrogen and progestin throughout the study phase, participating women were further asked to use active hormone pills throughout the study period in both studies, a practice that is considered both safe and efficacious.
Arms & Interventions
Fasted Evening Exercise (12h PMEx)
Exercise will take place in the evening, following a 12h period of fasting
Intervention: Fasted Evening Exercise (12h) (Behavioral)
Fasted Morning Exercise (12h AMEx)
Exercise will take place in the morning, following a 12h overnight fast
Intervention: Fasted Morning Exercise (12h) (Behavioral)
Fasted Evening Exercise (6h PMEx)
Exercise will take place in the evening, following a 6h period of fasting
Intervention: Fasted Evening Exercise (6h) (Behavioral)
Fed Morning Exercise (AMEx Fed)
Exercise will take place in the morning after consuming a small snack (30 min before exercise)
Intervention: Fed Morning Exercise (AMEx Fed) (Behavioral)
Fed Evening Exercise (PMEx Fed)
Exercise will take place in the evening after consuming a small snack (30 min before exercise)
Intervention: Evening Fed Exercise (PMEx Fed) (Behavioral)
Outcomes
Primary Outcomes
Acute ad-libitum post-exercise energy intake (test meal)
Time Frame: 30 minutes after exercise
Acute post-exercise energy intake (kcal) will be measured objectively using a single-item ad libitum test meal occurring 30 minutes after each exercise session. The meal will consist of cheese pizza, offered in excess of individual daily energy requirements, and all food will be provided at once.
Secondary Outcomes
- 24h post-exercise energy intake(24 hours post-exercise)
- Subjective appetite measures(before exercise, immediately after exercise, and 30 minutes after exercise)
- Carbohydrate oxidation(continuously throughout the 30-minute exercise bout)
- Energy expenditure(continuously throughout the 30-minute exercise bout)
- Fat oxidation(continuously throughout the 30-minute exercise bout)
Investigators
Karsten Koehler
Prof. Dr. Karsten Köhler
Technical University of Munich