A woman subsists on 900 calories a day. A six-foot-tall stick figure of a man weighs 115 pounds.
These are not victims of famine or anorexia, but high-functioning Americans seeking longer, healthier lives by eating a nutritious yet meager diet that forces their bodies to continually function on the brink of starvation. In return, they hope to extend their lives by years, if not decades.
Such a self-abnegating lifestyle that promises so much smacks of new age prophecy: Kool-Aid for a cult of waifs. Yet scientific evidence supporting the diet—rather blandly referred to as Calorie Restriction—continues to mount.
Science of Starvation
The theory dates back to 1935 when Clive McCay, a nutritionist at Cornell University, discovered that mice consuming 30 percent fewer calories lived 40 percent longer than mice that ate as they pleased. Since then, countless experiments with mice as well as with yeast cells, worms, and spiders have bore similar results. Recent findings on rhesus monkeys offer the greatest hope for humans. The monkeys that have been on Calorie Restricted (CR) diets for twenty years were less likely to die of age-related illnesses and retained better brain capacity for decision-making and controlled movement than their unrestrained counterparts.
No one has figured out why sharply decreasing calorie consumption and lowering metabolic activity would promote longevity. One leading explanation theorizes that nearly starving the body thrusts it into a maintenance mode; it concentrates on staying healthy and preserving its cells as opposed to say, breeding. (A lowered libido is considered a common side effect of an extremely low calorie diet.)
A Calorie-Deprived Movement
After conducting his own CR mice experiments in the 1960s, UCLA Professor Roy Walford became convinced that a restricted diet was the key to living longer. He wrote the CR bible, Beyond the 120-Year Diet: How to Double Your Vital Years, and in 1994 he and others founded the Calorie Restriction Society.
Loosely defined, a CR diet cuts caloric intake by 30 percent. A man practicing CR might eat about 1,800 calories a day, 900 calories less than an average American male. Walford’s own 1,600 calorie a day diet typically consists of a breakfast of a low-fat milk shake, a banana, some yeast and berries, a large salad for lunch, and a small portion of fish, a baked sweet potato, and some vegetables for dinner. Lean and muscular into his seventies, he was 5'8" and weighed just 134 pounds. But the stringent diet was not his elixir for an extraordinarily long and disease-free life. In 2004, he died from Lou Gehrig’s disease at seventy-eight.
