Researchers in Brazil, Austria and Portugal concluded that exercise and L-leucine supplementation induced an “acute inflammatory balance” and seemed to improve appetite control.
“Sprint exercise had a consistent acute anorexic effect, while isolated L-leucine decreased SPA, but their impact on SPS and food intake is not clear,” they wrote in the journal Nutrients.
They also noted that “sprint exercise associated with L-leucine supplementation in persons with overweight has the potential to improve appetite control.”
Satiety dysregulation
High-carbohydrate or high-fat diets may cause chronic, low-grade inflammation and dysregulation in obese individuals’ satiety mechanisms in the brain.
Previous research shows that the branched-chain amino acid L-leucine may affect neuronal pathways involved in appetite regulation, acting as an ‘insulin mimicker’ and producing an anorexic effect in animal models.
The current researchers previously found that individuals with overweight and obesity may not respond to L-leucine supplementation due to insulin resistance.
They hypothesized that exercise, a well-known strategy for regulating insulin, could overcome insulin resistance and, when combined with L-leucine supplementation, help reduce appetite in these individuals.
The effects of exercise also go beyond mimicking insulin. Acute physical exercise can increase neuropeptides such as GLP-1 and CCK, while decreasing ghrelin, thus maintaining satiety.
Additionally, exercise may help to regulate inflammation, having “a direct implication in improving insulin and leptin sensitivity and appetite control,” the study noted.
Study details
The double-blind, randomized, counterbalanced, crossover study involved 12 sedentary, overweight adult men who completed four experiments.
The four experiments were exercise and L-leucine (EX-Leu), exercise and placebo (EX-PLA), L-leucine without exercise (SED-Leu) and placebo without exercise (SED-PLA), and each experiment lasted three days.
Participants received three daily doses of 70 mg/kg body weight of L-leucine or placebo, and those in the exercise group completed a high-intensity sprint cycling session. Food intake was assessed using a questionnaire and blood samples were taken to evaluate neuropeptides and inflammatory markers.
“The main finding of this study was that, in overweight men, the short high-intensity sprint exercise combined or not with L-leucine supplementation was associated with a decrease in the subjective perception of appetite, improved satiety, and consequently a decreased caloric intake on the day of physical exercise,” the researchers wrote.
They also found that isolated supplementation of L-leucine was associated with a decrease in appetite perception, but there was no significant difference in satiety without the exercise.
“Another important finding was that the change in the subjective perception of appetite and satiety, as well as caloric intake, was significantly associated with inflammatory balance and neuropeptide concentration.”
They noted that distinct neural mechanisms regulate appetite and satiety, and that their assessment methodology for these processes could be improved.
Source: Nutrients 2026, 18(4), 614; https://doi.org/10.3390/nu18040614, “Acute L-Leucine Supplementation and Sprint Exercise Elicit Distinct Appetite and Inflammatory Responses in Persons with Overweight: A Randomized, Counterbalanced, and Crossover Design Study”, Authors: E. de Franca et al.
