We will examine fatty acid oxidation (FAO) and carbohydrate (CHO) oxidation at rest and during exercise in children of all body types and activity levels.~Children 8-11 years old who have done the MI Energy study will participate. Up to 80 children will be recruited to participate in this study at Arkansas Children's Nutrition Center (ACNC).~They will be asked to attend three study visits (baseline, and two exercise visits). For the exercise visits, they will follow a diet plan and be encouraged to avoid certain foods and activities.~Children will do two testing days with the following measures:~Urine (pee) will be collected~Body weight and height~Exercise test on the bike - children will ride a stationary bike at a set intensity and at an intensity relative to their previous bike test during the study MI Energy. The order in which they bike will be random. Before and during biking, children will wear a mask that will measure the gases in their breath and a monitor that will measure heart rate.
Children who have previously participated in the study MI Energy will be invited to participate in SUPER kids. Investigators want to better understand differences in nutrient use (e.g., fatty acid and carbohydrate) during rest and exercise in children of varying body types and activity levels.