Diet and exercise are key factors in preventing chronic diseases and delaying aging.

This paper is important because it is the first study in humans that strongly suggests that calorie restriction may delay primary aging.

If you put animals on a 30- or 40-percent calorie-restricted diet, they live 30 to 40 percent longer, and they have much less chronic disease.

We know people on calorie restriction will lose weight. But this study isn't a weight-loss study. We're hoping to learn more about whether calorie restriction can alter the aging process.

These studies strongly support the need to educate people to make sensible choices when they eat and that they need to exercise and walk more, instead of going by car everywhere.

The hearts looked 10 to 15 years younger.