Engaging in 3,000 kcal of aerobic exercise per week for 12 weeks leads to a reduction in body fat mass and percentage body fat in overweight adults, even when overall energy use and resting...
Mechanism
Synthesis from 1 study
Doing a lot of aerobic exercise burns extra calories, and your body responds by burning fat instead of slowing down your metabolism or making you eat more. Even though your hunger hormones go up, you don’t end up eating enough to cancel out the calorie burn — so you lose fat.
Most probable mechanism
When you do a lot of aerobic exercise, you burn more calories than usual. Your body responds by using stored fat as fuel to make up for the extra energy used, and it doesn’t slow down your resting calorie burn or make you eat more to balance it out — so you lose fat.
Aerobic exercise increases total energy expenditure, creating a sustained energy deficit over 12 weeks
The energy deficit triggers increased mobilization of fatty acids from adipose tissue into the bloodstream
Fatty acids are transported to skeletal muscle and oxidized in mitochondria to produce ATP, replacing glucose as a primary fuel source during prolonged activity
Resting metabolic rate remains unchanged, indicating no downregulation of basal energy expenditure
Total daily energy expenditure remains unchanged outside of exercise, indicating no reduction in non-exercise activity thermogenesis or other daily movements
Despite hormonal signals that increase hunger (elevated acylated ghrelin) and reduce satiety (decreased GLP-1), total energy intake does not increase significantly, allowing the energy deficit to persist
Less supported by current evidence, but not ruled out
Exercise might make food seem more rewarding, which could make people eat more, but in this case, that effect wasn’t strong enough to stop fat loss.
Exercise-induced energy deficit activates dopamine-related reward pathways in the brain, increasing the motivational value of food
Increased food reinforcement promotes food-seeking behavior and potential increases in energy intake
Food reinforcement decreased in the study, suggesting this pathway may be suppressed or overridden by other mechanisms
Evidence from Studies
Supporting (1)
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Energy compensation in response to aerobic exercise training in overweight adults.
Contradicting (0)
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