Eating for eternal youth: calorie restriction in right balance.(Innerbeauty: new strategies for vibrant living)

Since the 1930s, it has been known that calorie restriction (CR) prolongs life span and fends off age-related diseases in virtually all animal species tested. More recently, ongoing studies on primates suggest that same potential in humans.

"Humans were designed for hunting and gathering," says Stephen Cherniske, MS, nutritional biochemist and author of The Metabolic Plan: Stay Younger Longer (Random House, 2003) and the international bestseller The DHEA Breakthrough (Random House, 1998). "The agricultural revolution was great for making cities, but has been a disaster for humans. The amount we consume, what we consume, and how much we consume at one time is doing us in."

Cherniske spent time living with hunters and gatherers in New Guinea. "When they brought down a large boar, they didn't gorge on it. They divided it up and preserved the rest. In fact, I never saw them eat more than about 250 calories at a time. And these were the happiest people I've ever seen. When they first saw me prepare my American meal, they gathered around me, looking worried. When I asked the translator what the problem was, he said, 'They think you're going to explode.' And I eat a Spartan diet by American standards."

When Self-Deprivation Backfires

The standard approach to CR involves eating a low-fat diet. But before you start ordering your dressing on the side, eating your toast dry and cutting out other kinds of fat, consider your own potential compatibility with CR. Most researchers acknowledge that it takes a certain type of person to sustain CR. "Mother Nature's game is survival and procreation. To her, calorie restriction is a sign that there is insufficient food to provide for offspring. Reproduction plummets," says Cherniske.

Today, about one-third of adult Americans are insulin-resistant. This suggests that many may still experience elevated insulin--one of the surest roads to accelerated aging--on the low-fat diet recommended in most menu guides for CR. Granted, the conventional CR diet may be a dramatic improvement over what some people currently eat, but this trend toward insulin resistance in our population is food for thought for those dedicated to seeking the optimum diet (more on this subject next month), and it's one reason why conventional CR may work long-term for some but not for others.

Studies show that overweight people generally react poorly to low-fat diets, responding with elevated insulin levels (among other problems), which can contribute to accelerated aging. In his famous research at Stanford University, Gerry Reaven, who coined the term "Syndrome X" in the 1980s, discovered that older, overweight and insulin-resistant women on low-fat diets experienced elevated insulin and triglycerides while their lean counterparts fared much better. In addition, while CR prolongs youthful brain function in animals, one study published in the International Journal of Obesity and Related Metabolic Disorders found brain impairments occurred in obese women who went on CR diets.