Effects of dietary restriction on physical performance in mice

Dietary restriction is known to prolong life in laboratory animals. However, little is known about the effects of dietary restriction on physical performance. To evaluate physical performance, we measured four item indices: time to climb out of obstacles, time to escape restraint by gummed tape, time hanging from a bar, and ability to resist slipping every week. The diets of ICR mice were restricted from the age of 7 weeks through 24 weeks. Body weight of the diet-restricted mice decreased during the 7th to 9th weeks of age. After the 10th week, weight gain resumed. In response to assigned tasks, the diet-restricted mice performed better in all activities: they climbed out of obstacles faster, freed themselves sooner from restraint by gummed tape, hung from a bar longer, and better resisted slipping down a slope. These results suggest that diet-restricted mice have superior physical abilities, such as those required to overcome or avoid risks to life, than do ad-libitum-fed mice.