In sedentary overweight adult men, one session of high-intensity sprinting reduces how hungry they feel and how much food they eat on the same day, regardless of whether they take L-leucine.
Mechanism
Synthesis from 1 study
Sprinting hard makes muscles send a signal that calms down body-wide inflammation. This calm state lets the brain better detect when the stomach is full, so you feel less hungry and eat less. Leucine can also reduce hunger, but it works through a different, more inflammatory route that isn't needed...
Most probable mechanism
Intense sprinting causes muscles to release signals that shift the body's inflammation balance toward calming down. This calming signal makes the brain's appetite center more responsive to fullness signals from the gut, so the person feels less hungry and eats less.
High-intensity sprint exercise triggers metabolic stress and transient muscle damage, leading to release of interleukin-6 from skeletal muscle
Interleukin-6 stimulates production of interleukin-10 in liver and adipose tissue, establishing an anti-inflammatory feedback loop
Elevated interleukin-10 reduces inflammatory tone in the hypothalamus, improving sensitivity to satiety signals such as cholecystokinin and peptide YY
Enhanced hypothalamic sensitivity to satiety signals suppresses activity of orexigenic neurons, reducing subjective appetite perception and food intake
Less supported by current evidence, but not ruled out
Intense exercise combined with leucine intake causes a spike in inflammatory signals that directly act on the brain's appetite center to reduce hunger, even though this pathway is overridden by the anti-inflammatory effect when leucine is absent.
L-leucine activates mTOR and TLR4 signaling in immune and adipose cells, increasing production of interleukin-6, interleukin-1β, and tumor necrosis factor-alpha
Elevated interleukin-6 and interleukin-1β cross the blood-brain barrier and bind to receptors on hypothalamic neurons, suppressing appetite perception
Elevated tumor necrosis factor-alpha promotes food intake, but its effect is overridden when interleukin-6 is simultaneously elevated
A low interleukin-10/interleukin-1β ratio creates a pro-inflammatory state that enhances appetite suppression
Evidence from Studies
Supporting (1)
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Contradicting (0)
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