Updated on 4/25/2005
We've long known that most laboratory animals kept on a low-calorie diet live longer and enjoy better health than those allowed to eat more food. This method of extending longevity is called caloric restriction or under-nutrition. You may have read of a study published in the Sept. 19, 2003 issue of Science, which found that switching to a low-cal diet in middle age keeps fruit flies alive longer. We don't know yet whether the same holds true for humans, but the study suggests that it may never be too late to take action to improve your health.
Conducted by researchers at University College London, the study found that restricting the diets of fruit flies beginning at two to three weeks into their lives (middle age for a fruit fly) doubled their life span to 90 days. And it didn't matter whether caloric restriction was begun in infancy or middle age.
Many life extension researchers believe that caloric restriction would offer similar benefits to humans. (Studies in monkeys are now in progress.) But even if it does, how many people would be willing to follow such advice? Another line of research is looking at the mechanism by which under-nutrition works. Apparently, it must impact hormonal systems that regulate both appetite and aging.
Alternatively, caloric restriction may just allow a normal lifespan, meaning one that hasn't been shortened by overeating. Researchers may possibly find a way of producing the same end result with some intervention that allows people to continue to eat normally. That will be the ultimate free lunch, and it is not a total fantasy. This is a hot topic in aging research, and many investigators are working on it. Stay tuned. And in the meantime, continue to eat the kind of diet recommended on this site (varied, high in fresh foods, low in processed foods) and get regular exercise. This will help you maintain your weight and enjoy optimum health.
Andrew Weil, M.D.