Since the 1930s, scientists have been experimenting with animals to determine the link between caloric reduction and longer life spans. What they’ve learned has astonished them. Scientists have prolonged life by as much as 50 percent in these animals merely by reducing their daily caloric intake to about two-thirds of what is considered normal.

"They’ve experimented with insects, fish, some invertebrates and dogs, and they keep coming up with the same results," says Dr. Robert Keith, an Alabama Cooperative Extension System nutritionist and Auburn University professor of nutrition. "When you keep seeing the same thing over and over again among a variety of animals, you know there has to be some truth to all of this."

Scientists have now moved the studies a further up the scale to primates such as rhesus monkeys and chimpanzees. Primates live much longer than other animals, so it will be several years before these experiments are completed. Still, researchers are intrigued with what they’ve learned so far.

"The ones on the restricted diets are healthier and have fewer diseases – though they’re smaller and leaner -- while some of the members of the control groups (fed a normal diet) already have died," Keith says. "And they’re seeing the same effect with both species, rhesus monkeys and chimpanzees alike."

While the animals are placed on sharply restricted calories, they still receive adequate amounts of vitamins, minerals, proteins and other essential nutrients, he says.

What causes this spike in life spans? No one knows for sure, though scientists have determined animals on restricted diets have much slower metabolic rates and lower levels of oxygen consumption – factors, some scientists believe, may contribute to longer lives.

"It could indeed have something to do with oxygen consumption," says Keith. "We need oxygen to live, but it’s also a sort of double-edged sword, because in addition to providing life, it is also a free-radical producer."

Free radicals are known to cause cell damage throughout the body – damage that can lead to heart disease and certain forms of cancer over time. By reducing levels of oxygen consumption, Keith says, calorie reduction may contribute to reduced levels of free radicals in the body, thereby reducing the risk of developing these diseases.

One other theory may account for the effects associated with caloric restriction. Scientists do know that certain cells within the body divide only a limited number of times in the course of one’s life – in some cases, no more than about 50 times.

"After they divide 50 times, that’s it," says Keith. "It could be that some form of death mechanism is turned on or a protective gene turned off."

"By reducing calories throughout one’s life, perhaps we’re merely prolonging the point at which this limit is reached. Instead of dividing 50 times in, say, 80 years, it takes as long as 150 years for the final division to take place."

Even so, while scientists are intrigued with the findings, most are certain they’ll never persuade the average American to restrict his intake to the desired level.

"You’re talking about 1,200 calories a day for a woman and about 1,500 calories a day for a man," Keith says. "But a typical lunch comprised of a hamburger, fries and a soda adds up to about 1,000 calories."

"So, we’re supposed to be eating only about 1,500 calories a day, even though a typical meal amounts to about 1,000 calories. I doubt there are very many American men that could come close to restricting his calories to this amount."

"Women? Maybe a few, because of concerns about their personal appearance. But men? I seriously doubt it."

Largely for this reason, researchers already are trying to isolate the chemical effects in the body associated with caloric reduction so that one day, perhaps, all of the benefits associated with this lifestyle can be reproduced in a pill – a fountain of youth in a bottle.

(Source: Dr. Robert Keith, Extension Nutritionist, 334-844-3273)

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