The Exercise-Nutrition-Obesity Cycle

The effect of exercise on energy balance is not limited to its related energy expenditure, but also to post-exercise effects on appetite, food preferences and energy intake. Despite recent increased scientific interest, very little is known about these relationships in childhood obesity. Low socio-economic and minority pre-school children demonstrated reduced nutritional and physical activity knowledge and preferences. However, a significant improvement in the knowledge level of high socio-economic children was found following combined behavioral-nutritional-exercise interventions. While exercise was associated with reduced immediate caloric intake among normal-weight children, an increase in caloric intake (mainly proteins) was found among pre-pubertal obese children, particularly following swimming. Other studies demonstrated a significant decrease in caloric intake later in the day, particularly at dinner time, in obese adolescents. Despite the notion that exercise training increases appetite, prolonged training resulted in reduced energy intake in obese adolescents. Increased appetite is speculated to occur only above a threshold level of physical activity. The activity level that obese children perform in exercise interventions is usually below this threshold. Further research is needed to improve our understanding of the convoluted exercise-appetite-nutrition-obesity cycle. Such knowledge is warranted in order to optimize childhood obesity weight management programs.