Energy Intake, Hormones, Satiety, Substrate Utilization
Conditions
Brief summary
Exercising in the fasted state results in greater fat oxidation during exercise and results in decreased caloric intake in the meals after exercise. However, the studies that examine fasted vs. fed exercise utilize a carbohydrate-based breakfast, which can increase blood glucose and insulin concentrations, which is considered a negative consequence. A protein breakfast, which can increase satiety and rest of day energy intake could also increase resting energy expenditure as well as fat oxidation during exercise. However, comparisons between fasting exercise and pre-exercise breakfast macronutrient intake (i.e., carbohydrate vs. protein) have not been made. Therefore the purpose of this study is to investigate if eating breakfast and the composition of this breakfast before exercise has an effect on the food eaten throughout the rest of the day.
Interventions
DIETARY_SUPPLEMENTMaltodextrin supplement
maltodextrin (25g in 12 oz water) 1 hour pre-exercise
DIETARY_SUPPLEMENTWhey supplement
whey (25g in 12 oz water) 1 hour pre-exercise
DIETARY_SUPPLEMENTWater
non-caloric control (12 oz flavored water) 1 hour pre-exercise
Sponsors
Ohio University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
MALE
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* 18-45 years old * regularly participate in exercise for at least 150 min per week * run at least 3 days per week for 30 minutes * able to complete a VO2max test * able to exercise for 45 min moderate intensity exercise at one time without breaks
Exclusion criteria
* not participating in structured exercise of 150 min/week for the past 6 months * not running at least 3 days per week for 30 minutes * not attaining a VO2max of 50 ml/kg/min (60th percentile fitness classification according to the American College of Sports Medicine) * currently smoke or quit smoking less than one year ago. * diagnosed with or are being treated for a cardiovascular disease, high blood pressure, fibromyalgia, irritable bowel syndrome or a metabolic disorder such as diabetes, thyroid disorder, or high cholesterol. * food allergies or sensitivities. * not willing to have blood drawn on 4 occasions during each trial (16 total times)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in energy expenditure | immediately pre-breakfast, immediately post-breakfast, immediately pre-exercise, and immediately post-exercise | Measured via indirect calorimetry |
| Change in lunch energy intake | 60 min post-exercise | measured via standardized lunch buffet |
| Change in dinner energy intake | Day 1 (trial 1); between Days 6 and 8 (trial 2); between Days 11 and 15 (trial 3); and between Days 16 and 22 (trial 4) | weight of food returned the following day |
| Change in appetite | immediately pre-breakfast, immediately post-breakfast, immediately post-exercise, and immediately pre-lunch | measured via circulating hormones |
| Change in blood glucose | immediately pre-breakfast, immediately post-breakfast, immediately post-exercise, immediately pre-lunch, and immediately pre-dinner | measured via fingerstick blood assessment |
| Change in subjective hunger | baseline, immediately pre-breakfast, immediately post-breakfast, immediately post-exercise, immediately pre-lunch, immediately post-lunch, immediately pre-dinner, and immediately post-dinner | measured via 100mm visual analogue scale, higher scores indicate greater hunger |
Countries
United States
Outcome results
None listed