Eating less may help in living a long and healthy life, indicates a Canadian study. Russ Hepple, a physiologist, along with other researchers at the University of Calgary examined the effects of calorie restricted diets on rats and found that elderly rats on such diet had the muscle mass and function of a 20-year-old rat, reported science portal The News Medical. These rats, bred at the US-based National Institute of Aging, were fed a diet rich in nutrition but 40 percent lighter in calories than normal from a very young age. At the same time, the rats that were fed a normal diet lost 50 percent of their muscle mass as well as muscle function at old age, the study found. The study also discovered that elderly rodents on a strict diet experienced only a 20 percent drop in muscle mass with no loss of muscle function. The researchers say it has been known for some time that a calorie restricted diet extends life span by as much as 35 percent, but they have now found that it also maintains muscle function. Apparently the diet appears to help the aging rats rebuild and replace muscle and, Hepple says, it is unclear why. He suggests a restricted-calorie diet preserves the function of mitochondria, which provides energy to body's cells as the animals grow old. Despite evidence that reducing calories has a profound impact on the muscles of rats, Hepple does not suggest that people follow suit and cut their food intake by 40 percent. His advice is instead that humans eat a healthy diet, refrain from overindulging and remain active to maintain their muscles. A similar diet for humans can be drastic and possibly destructive to muscle, especially if the calories come from protein, he warns.