Acute L-Leucine Supplementation and Sprint Exercise Elicit Distinct Appetite and Inflammatory Responses in Persons with Overweight: A Randomized, Counterbalanced, and Crossover Design Study.

EX-Leu, EX-PLA, and SED-Leu all decreased subjective perception of appetite (SPA) compared to SED-PLA, but only EX-PLA improved subjective perception of satiety (SPS).

• Study used a double-masked, randomized, counterbalanced, crossover design with 12 sedentary overweight adult men.
• Four experimental conditions were compared: exercise + L-leucine (EX-Leu), exercise + placebo (EX-PLA), sedentary + L-leucine (SED-Leu), and sedentary + placebo (SED-PLA).
• Only the exercise-placebo condition (EX-PLA) significantly improved satiety perception, distinguishing it from both leucine-alone and combined conditions.
• Isolated L-leucine supplementation decreased SPA but did not significantly improve SPS compared to SED-PLA.

Sprint exercise reduced food intake regardless of leucine supplementation, while isolated leucine supplementation did not significantly reduce food intake.

• EX-PLA and EX-Leu both reduced food intake compared to sedentary conditions.
• SED-Leu did not produce a clear reduction in food intake relative to SED-PLA.
• The acute exercise protocol consisted of four sets of 30-second cycle ergometer sprint exercises.
• The authors noted that the impact of isolated L-leucine on food intake was 'not clear.'

GLP-1 levels decreased in the EX-PLA trial compared to SED-Leu.

• GLP-1 is one of four neuropeptides measured in peripheral blood, alongside PYY, CCK, and ghrelin.
• The decrease in GLP-1 was specific to the EX-PLA comparison with SED-Leu.
• Neuropeptide changes (increased levels) were associated with changes in SPA, SPS, and food intake across conditions.

IL-6 and IL-1β levels were elevated in the EX-Leu trial compared to SED-PLA, indicating a pro-inflammatory response when sprint exercise was combined with L-leucine supplementation.

• Cytokines measured included IL-1β, IL-6, IL-10, and TNF-α in peripheral blood.
• The EX-PLA trial demonstrated an anti-inflammatory profile compared to the other three experimental trials.
• The EX-Leu combination produced a pro-inflammatory cytokine profile distinct from the anti-inflammatory profile seen with exercise alone.
• Pro-inflammatory cytokine profiles were associated with changes in SPA, SPS, and food intake.

The acute inflammatory balance induced by the combination of exercise and L-leucine (EX-Leu) appeared to improve appetite control.

• The authors concluded that 'the acute inflammatory balance induced by EX-Leu seems to improve appetite control.'
• Both neuropeptides and cytokines were associated with changes in subjective appetite, satiety, and food intake.
• The pro-inflammatory profile in EX-Leu was contrasted with the anti-inflammatory profile in EX-PLA.
• This finding suggests cytokine responses play a role in appetite regulation following combined leucine supplementation and sprint exercise.

L-leucine supplementation was administered as three daily doses of 70 mg/kg body weight on the day of exercise and one day after.

• The study was double-masked with placebo control for leucine supplementation.
• The same dosing regimen (70 mg/kg body weight, three daily doses) was used for both the EX-Leu and SED-Leu conditions.
• Supplementation extended beyond the single exercise session to the day following exercise.
• 12 sedentary overweight adult men completed all four experimental conditions in a crossover design.