Caloric Restriction & Long Life

It happened long ago, and yet popular culture lacks knowledge of ground-breaking experiments on how to live longer. The year was 1934. The scientists were Clive McCay and Mary Crowell of Cornell University. The experiment was simple. McCay and Crowell fed laboratory rats a diet with severely reduced calories while insuring nutrition remained adequate. This diet resulted in life spans twice as long as otherwise expected. In humans, a calorie-restricted diet could lead to life spans of 115 to 120 years, the maximum that longevity evidence indicates. That increase in years would be attended by relatively good health until death.

Roy Walford and Richard Weindruch conducted similar experiments on mice. In 1986, Weindruch reported that restricting the calorie intake of laboratory mice proportionally increased their life span compared to a group of mice with a normal diet. The calorie-restricted mice also maintained youthful appearances and activity levels longer and showed delays in age-related diseases. Walford and Weindruch summarized their findings in a book, The Retardation of Aging and Disease by Dietary Restriction (1988).

The findings apply to more than rats and mice. Many people have taken up the practice of caloric restriction (CR) and there are web sites dedicated to it. Because life is short, they have chosen not to wait for research on the possibility of parallel physiological links in humans.

The findings have been significant. In 2002 at Washington University, 30 participants were engaged in trials on longevity and caloric restriction. Dr. Luigi Fontana found that the practitioners appear to age more slowly than the general population. In the caloric restriction group,with a mean age of 55, systolic blood pressure had a mean of 110, about that of a 20-year-old. More here and here.