Dietary influences on nonexercise physical activity and energy expenditure in C57BL/6J mice

It is well established that the lack of physical activity can lead to weight gain or obesity. However, there is limited information on influences of diet components on physical activity. Thus the purpose of this study was to investigate the role of major dietary components on energy expenditure by affecting nonexercise physical activity in C57BL/6J mice. All mice were assigned to 1 of the following 4 dietary groups based on their body weight and baseline physical activity; low fat/normal protein, high fat/normal protein, low fat/low protein, or low fat/high protein. After 3 mo, the highest weight gain was observed in animals fed with high-fat/normal-protein diet, and the caloric intake was significantly lower in low-fat/high-protein diet-fed mice compared to other groups. However, there were no significant changes in nonexercise physical activity during experimental periods in all groups. The respiratory quotient and energy expenditure were not significantly different among the dietary groups. These findings suggest that diet-induced obesity is not explainable by levels of physical activity and energy expenditure. PRACTICAL APPLICATION: The understanding the link between diet and nonexercise physical activity would provide important knowledge that will potentially assist appropriate food choices to control obesity and its related health problems.