The only scientific proven way to increase longevity. In 1935 it was found that the lifespan of laboratory rats could be extended by as much as 50% on severely calorie restricted diets, the rodent equivalent of a human life stretched past the age of 160. And it isn’t just a mouse. Yeast cells, spiders, worms, monkeys have all been shown to benefit from CR’s life-extending effects.

In 1991 a team of eight bioscientists sealed themselves up for a two-year stint inside a giant, airtight terrarium in the Arizona desert, and promptly discovered that the hypothetically self-sustaining ecosystem they’d settled into could barely grow enough food to keep them alive.

This revelation might have doomed the experiment (known as Biosphere 2) but for the fact that the team’s physician, UCLA pathologist Roy Walford, had been studying Calorie Restriction for decades and convinced his fellow scientists that—as long as they all ate carefully enough to get their daily share of essential nutrients—a year or two of near starvation wouldn’t hurt.

When at last the Biosphere 2 crew emerged from their bubble, tests proved them healthier in nearly every nutritionally relevant respect than when they’d gone in, and the case for Calorie Restriction in humans was no longer purely circumstantial.

So what are the benefits of CR?

Dr. John Holloszy, principal investigator of a long term study on CR has this to say, "There's no chance of CR practitioners getting type 2 diabetes, they have very low blood pressure, and the risk of them developing heart disease and cancer is markedly decreased," "The calorie restriction protects them from the same diseases that exercise protects against, and more potently than exercise,"

And exercise? Not an option as C.R. dieters simply don't have the calories for it, unless they increase their calories accordingly.

Dr Hellerstein a professor at UC Berkeley, says "It's the only thing that is known to extend the life span in animals," he studies human nutrition and metabolism. He recently started recruiting people for a study where subjects will eat a near-fasting diet every other day, alternated with a normal one. "It's the most amazing thing in all of biology."

And there is a growing impetus to find out if humans reap the same benefits, over time, as lab animals. The Baby Boomers are aging, and just as they felt the need to revolutionize attitudes toward child rearing and midlife, they are interested in a better old age. They are the ones who promoted 50 as the new 40. Could 100 will be the next 90 - or 80?

The National Institute on Aging and National Institutes of Health are both funding research at major universities. Private industry is also studying the metabolic effects of CR, working to create a pill that will mimic it and bypass the need for a rigid diet.

An example is 47 year old Joseph Cordell who eats about 30 % fewer calories than most people. The recommended minimum is 2,500 calories for adult males. Those males practicing CR commonly consume 1800 to 2000 calories daily while some women might consume as few as 1300 calories to 1500 calories daily.

Cordell's doctor says that he has the blood pressure of a child, the cholesterol of a teenager, and his risk of heart disease is close to zero. Average middle-aged men have 23 to 25 percent body fat; Cordell's is 7 percent.
"If there wasn't a substantial benefit to C.R., no one would do it," he says.

For Cordell, the potential payoff is worth eating this way, something many of us might have a hard time with. It's not about a short term New Year’s resolution; it's about a complete diet overhaul that Cordell will stay on for what he believes will be a longer, healthier life.

Barry Gamble a 67 year old CR advocate says his benefits are more energy, fewer digestive problems, better measures of heart health and mobility than his peers and although there are no guarantees, a longer life. "The real reason I do it is because I feel better.”

The focus of those practicing CR is health. Nobody is trying to figure out how to eat less and disappear. The constant thought is, ‘How can I pack more nutrition into my calories?’

Theory of how CR promotes longevity

Inside our cells the process of cellular respiration breaks down a molecule of glucose into carbon dioxide, water, and energy. This energy is stored as ATP. An adult produces 70kg of ATP a day. The process of breaking down sugar in the body is not completely efficient. About 40% of the sugar is converted into ATP. A significant amount of free radicals are produced during this process. When calories are restricted our bodies rely more on fat stores as fuel.

Since fat consumption is several times as efficient at producing ATP than burning glucose, the same amount of energy can be created with much lower levels of free radicals. Fewer free radicals mean lower levels of free radical damage particularly to the mitochondria. Recent studies have shown that a calorie restriction of 40% leads to a 45% decrease in the rate of mitochondrial free radical generation and a 30% reduction in the level of oxidative damage to mitochondrial DNA.

The net effect of these changes decreases the rate of aging by about 50%. Unfortunately humans cannot live reasonably by cutting 40% of their calorie intake. But by decreasing our calorie intake by 15% one achieves almost as much of an anti-aging benefit. It becomes a more realistic achievement than the tough 30% reduction often used by the calorie restriction purists.

CR followers say it is "a way of living" instead of a diet. The Calorie Restriction Society, based on the work of the late UCLA gerontology researcher Roy Walford, was founded in 1994 by a small group of people interested in the science behind CR and an estimated 1,400 people have taken up the diet as a full-time, lifelong practice.

What should you do while waiting for the long term human studies? If you are overweight or you want to experience the potential anti-aging benefits of CR it would be prudent to reduce calories by 15%.

We need to work together with our health practitioner and monitor our blood levels of glucose, insulin, cholesterol and inflammation levels. We need to do this slowly over time and according to the CR followers we will then experience optimal health.