Nutritional Responses to Acute Exercise Performed on the LipoxMax in Obese Adolescents

Our team has indeed demonstrated the appetite-suppressing effects of moderate- to vigorous-intensity exercise (>65% of maximum capacity) in obese adolescents, regardless of gender. While research conducted to date has primarily focused on identifying the characteristics of exercise that can influence food intake in these adolescents-such as the type, intensity, or duration of exercise-it appears that, beyond physical exercise itself, the energy substrates utilized during exercise may play a crucial role.

In adults-whether of normal weight, overweight, or obese-the scientific literature highlights not only the energy expenditure generated by physical exercise but also the vital role played by the type of energy substrate used to fuel this expenditure. Indeed, while physical exercise that primarily promotes lipid oxidation does not appear to significantly impact eating behavior at the next meal, carbohydrate utilization, on the other hand, appears to have a rather appetite-stimulating effect. Although this nutritional impact of the types of energy substrates utilized during physical exercise is crucial for better guiding our recommendations for adapted physical activity, it remains unexplored in adolescents at this time. Recently, based on a secondary analysis, our team suggested a positive correlation between energy expenditure during a 30-minute cycling exercise and subsequent food intake in adolescents with obesity. In that study, carbohydrate oxidation in particular showed a positive relationship with the adolescents' food intake at the next meal. These preliminary results led to a study dedicated to this question; however, that study unfortunately did not replicate this relationship and appears to indicate that carbohydrate utilization during acute exercise is not involved in short-term dietary regulation in these adolescents.

However, that study had focused its design on an exercise regimen that promotes carbohydrate utilization, and the potential role of fat oxidation remains unexplored in this population. In overweight adults, Javernaud and colleagues previously demonstrated that exercise targeting the maximum lipid oxidation point (known as Lipoxmax) reduced feelings of hunger in the hours following the workout while improving participants' satiety. While prescribing physical exercise as a key component of pediatric obesity management is considered essential for optimizing treatment outcomes, the potential impact of exercise performed at Lipoxmax on food intake remains unexplored in this population.

Thus, in this context, the objective of this study is to explore the effects of a single session of exercise performed at the maximum lipid oxidation point (Lipoxmax) on dietary control in adolescents with obesity.