This study's primary aim is to investigate the acute effect of an exercise bout (30 minutes) on appetite and appetite-regulatory hormone responses during energy restriction. The researchers will also test if the exercise bout influences ad libitum energy intake after a period of energy restriction. The researchers will compare three groups (control, severe-energy restriction, and severe-energy restriction with exercise) to see if exercise bout, during energy restriction, affects appetite, appetite-regulatory hormones, and energy intake in healthy men.
Before the main experiments are conducted, participants will attend a screening visit where the participants will provide consent and complete questionnaires that assess their health, food preferences, and physical activity levels. Researchers will then measure the participants' height, weight, waist circumference, and body composition. Once the eligibility criteria are confirmed, participants will participate in two treadmill tests to establish their maximum oxygen uptake (V̇O2 max). After the screening visit, participants will participate in three main experiments, each lasting 24 hours: control, severe energy restriction, and severe energy restriction with exercise. These experiments will be conducted in a counterbalanced design. Each experiment will start around 9:30 AM, following an overnight fast of at least 10 hours. Participants will have a prescribed meal in the evening before each main experiment. After this meal, the participants are only allowed to drink water until the start of the main experiments. During the exercise trial, participants will begin by running on a treadmill for 30 minutes at a speed estimated to achieve 75% of their V̇O2 peak, followed by a rest period in the laboratory. The same protocol will be followed in the control and severe-energy trials, except that no exercise will be performed. Participants will rest in the laboratory during both the control and energy-restricted trials. In the control trial, the participants will receive 100% of their estimated energy needs; in the energy-restricted trials, the participants will receive only 25%. The participants will have standardized breakfast and lunch meals at 1h and 5h, respectively. At 24h, participants will be provided an ad libitum buffet meal in a private eating room. The researchers will assess appetite ratings in each experiment using 100 mm visual analog scales. The researchers will also collect blood samples to analyze ghrelin, peptide YY (PYY), glucagon-like peptide 1 (GLP-1), and potentially other blood-borne measures.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
14
The participants will receive only 25% of their estimated energy needs.
The participants will run on the treadmill for 30 minutes and receive 25% of their estimated energy needs.
New Lister Building, Glasgow Royal Infirmary
Glasgow, United Kingdom
RECRUITINGChange in Peptide-YY (PYY)
The researchers will draw blood samples at different time points during the trial to measure the change in PYY blood levels. Area under the plasma concentration versus time curve (AUC) of PYY will be calculated using the trapezoidal rule.
Time frame: At 0 (baseline), 0.5, 1, 1.5, 2, 3, 4, 5, 5.5, 6, 6.5, 7, and 23 hours
Change in Ghrelin
The researchers will draw blood samples at different time points during the trial to measure the change in ghrelin blood levels. Area under the plasma concentration versus time curve (AUC) of ghrelin will be calculated using the trapezoidal rule.
Time frame: At 0 (baseline), 0.5, 1, 1.5, 2, 3, 4, 5, 5.5, 6, 6.5, 7, and 23 hours
Change in Glucagon-Like Peptide-1 (GLP-1)
The researchers will draw blood samples at different time points during the trial to measure the change in GLP-1 blood levels. Area under the plasma concentration versus time curve (AUC) of GLP-1 will be calculated using the trapezoidal rule.
Time frame: At 0 (baseline), 0.5, 1, 1.5, 2, 3, 4, 5, 5.5, 6, 6.5, 7, and 23 hours
Change in subjective appetite sensations
The researchers will assess the subjective appetite sensations using 100 mm visual analog scales (VAS) to measure appetite sensations (hunger, satiety, fullness, prospective food consumption, and desire to eat). The VAS are 100 mm long, with words anchored at each end expressing the most positive and negative ratings. Scores for each appetite construct range from 0-100.
Time frame: At 0 (baseline), 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 5.5, 6, 6.5, 7, 23, 24, and 25 hours
Energy Intake
To determine the amount of each food item consumed, the researchers will measure the difference in weight between before and after the meal. The researchers will use manufacturer details to determine energy consumption.
Time frame: At 24 hours
Macro-nutrient Intake
To determine the amount of each food item consumed, the researchers will measure the difference in weight between before and after the meal. The researchers will use manufacturer details to determine macro-nutrient consumption.
Time frame: At 24 hours
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