Eat Less, Live Longer?

The benefits of a calorie-restricted diet were first seen in 1934 when a group of researchers at Cornell University observed that the lives of rats extended by 33 percent when the rodents' calorie intake was restricted. Results were first seen in humans almost by accident. In 1991 eight scientists entered a man-made, materially closed ecological system in Tucson, Ariz., known as Biosphere 2 to study man's influence on the ecosystem. The biosphere was unable to produce as much food as the scientists had predicted, forcing the researchers onto a nutrient-packed, extremely low-calorie diet. Roy Walford, the group's physician and an expert in calorie restriction and aging, noted that despite weight loss, the group's mental and physical activity levels were excellent; their blood pressures and cholesterol levels dropped.

A 2004 study published in the Proceedings of the National Academy of Sciences detailed the results of humans who have practiced the calorie-restriction diet for a long period of time. The study's subjects had lower cardiovascular risk factors and extremely high levels of HDL (or "good" cholesterol), and triglyceride levels were comparable to or lower than Americans in their 20s, despite the fact that all the study's participants were between the ages of 35 and 82.

Still, the mechanisms behind the diet's success are still unknown. One general theory is that the diet puts the body into survival mode, causing cells to be extremely efficient, boosting the process by which cells remove damage. Research has shown that these unrecycled or damaged cellular components can lead to age-related decline.

Despite the positive results of this study, caution is advised before jumping into the CR diet. "You need to make sure you do things properly," says Bonnie Taub-Dix, registered dietitian and national spokesperson for the American Dietetic Association, who says issues of malnutrition are a concern. "Even then, it's not a guarantee of living longer. Some people eat lousy diets and have great genetics; others take good care of themselves but have poor genetics. One plus one doesn't always equal two."

Although Cavanaugh is very careful about his nutritional intake, he'll occasionally give in to his sweet tooth, or he and his wife will splurge on dinner out—though he says a steak, which he occasionally enjoys, "just tears my stomach up" due to the high fat content. He still eats birthday cake (400 calories) at his grandchildren's parties, a glass of red wine (124 calories) with dinner "six nights out of seven," and every Thursday he can be found sipping a beer with his friends down at the local cigar bar.

The rest of the time, dinner typically consists of a small portion of lean meat, chicken or fish; a big salad; and fruit and yogurt for dessert. After, Cavanaugh eats his two daily canned oysters to supply the zinc and copper he needs and a handful of nuts, including two Brazil nuts to provide selenium.

Then he and his wife head to the porch. They smoke and watch the sunset. "I used to think about life as being on a conveyor belt. You got on and traveled to the end, then died. But when I got into learning more about CR, it changed my whole outlook on life," he says. "I still see it as a conveyor belt, but now I know that I can regulate the speed of it. I can slow it down. Living to be 100 is now a definite goal."

© 2009