Extreme Dieting: Fountain Of Youth?

Eat less, alot less, and live longer and feel younger.

That's the boiled down philosophy of a small but growing movement called "Calorie Restriction."

As The Early Show medical correspondent Dr. Emily Senay explained Tuesday, research in animals such as mice, dogs, monkeys, even cows, has repeatedly shown that carefully restricting calories increases life spans.

But will it work in humans?

The believers in Calorie Restriction (www.calorierestriction.org, and, beginning Wednesday, www.livingthecrway.com) are counting on it, Senay reports.

Paul McGlothin, board chairman of the Calorie Restriction Society, and Meredith Averill, the group's research head, say consuming fewer calories means more life.

"Calorie restriction," Averill told Senay, "is taking in fewer calories than the body needs, or thinks it needs" to maintain its current weight.

Averill says she eats 1,600 calories-worth of food each day, as opposed to the conventional medical recommendation for a woman her size and age of 2,000.

"It's not about the weight loss," McGlothin observes, "it's about being as healthy as you possibly can."

In other words, Senay says, staying healthy longer and slowing the aging process.

At 59 and 61, McGlothin and Averill say they feel years younger, with sharper memories and perhaps even more energy.

Restricting calories in laboratory animals has been shown to affect cell behavior that may be involved in age-related diseases such as Alzheimer's, heart disease, and cancer, Senay points out. What's more, it's been shown to increase lifespan: Mice lived 30 percent longer than usual on calorie-restricted diets.

But dietician Elisa Zied, a spokesperson for the American Dietetic Association, says Calorie Restriction is too severe, and the animal research can't easily be translated to humans' health.

Notes Zied, "We have no clinical data in humans to supports calorie restriction to have all these benefits. So, I think people really need to read between the lines, and I don't think, in our lifetime, we're ever going to really see that Calorie Restriction is the fountain of youth."

Still, it's the lab findings that motivate people such as Dr. Steve Bell to attend workshops such as the one at which Senay chatted with him, sessions sponsored by the Calorie Restriction Society.

"I practice functional, integrated medicine," Bell says, "where lifestyle is the keynote component, and I think there's a lot of research in the anti-aging literature about calorie restriction as being a way to extend life."

For many people, Senay says, calorie restriction doesn't necessarily mean choice restriction. But, calorie restrictors are very careful to control nutrients, vitamins and minerals.

A typical lunch for McGlothin and Averill includes vegetables, vegetable broth, and barley.

Also, time away from food, fasting, matters to them.

Asked what she planned to have for dinner on a given night, Averill responded, "A long walk."

But dieticians such as Zied argue that too few calories and long periods without food can jeopardize a person's health.

"Skipping meals is just setting you up for dietary disaster," asserts Zied. "You're basically not giving your body the energy it needs. And you need to give your body fuel every few hours to sustain your metabolism."

But McGlothin and Averill stress that fewer calories maximizes fuel to slow down aging, and may be key to happiness.

All in all, says Averill, "Right now, life is better."

She and McGlothin say they work closely with their doctors to make sure they stay healthy, and are very careful not to go below government guidelines for weight. They're also involved in a clinical trial of calorie restriction, and plan to put out a book on it early next year.

Senay stressed that calorie restrictors say they're different from anorexics in that they're not about losing weight, they're not about harming themselves, they're all about getting as much nutrition as they can into a reduced calorie diet.