Low-calorie longevity: the anti-aging diet

Want to live longer? How does 120 or more sound? That's realistic, say many anti-aging researchers. But at present, you'd have to switch to what longevity researchers call a "calorie-restricted" diet.

It sounds like dieting, but it isn't. Dieting has the short-term goal of weight loss. But caloric restriction--or CR--represents a lifelong approach to food consumption.

CR, however, doesn't mean starvation. In fact, the objective is to consume fewer calories without sacrificing nutrition.

Through good food choices and supplements, a CR diet is fortified generously with vitamins, minerals and antioxidants to provide the same nutrients as an unrestricted diet--but with substantially fewer calories.

While calorie restriction sounds, well, restrictive, scientists say it's more aptly called the "anti-aging" diet or the "high/low" diet--high in good nutrients, low in bad. That's why half-starved people in famine areas derive no longevity benefit: their low-calorie intake lacks nutrient density.

Caloric restriction isn't a new idea. Since the first experiment in 1935 at Cornell University, in Ithaca, New York, researchers have collected over 2,000 studies concluding that CR can extend animal lives drastically and delay the onset of age-related illnesses. And according to US government scientists writing in the mid-1999 edition of the Journal of Nutrition, Health and Aging, "The well-known effects of CR on lifespan, disease and aging processes may be generalizable to all species."

In fact, caloric restriction is the only strategy to date that has been scientifically proven to extend the "maximum life span"--the term for the technical limit to life, different in each species.

In humans, the maximum life span runs about 110-120 years. You can inherit great genes, eat well, exercise and always buckle your seat belt, but you just can't rise above that ceiling. Or at least you can't without a CR diet.

Meanwhile, CR needn't mean a Spartan and hungry existence. The degree of restriction is your choice, and it's not an all-or-nothing phenomenon. Even a 10 percent restriction in calories has a measurable, beneficial effect. Just cutting out fatty foods or skipping lunch could be enough.

Because sudden caloric reductions may be harmful, scientists suggest gradually transitioning to a CR diet over one to two years--a hardly noticeable shift in calories. Some may opt for periodic fasting instead.

Sixty percent of Americans--and one billion people worldwide--are overweight. Most want to be thinner anyway; but the idea of living a lot longer adds a powerful incentive to eat less.

Walford's research indicates that if you exercise the calories away, you don't get the same longevity benefit.

It's not your weight that counts, but how many calories you consume. If you want to live substantially longer, you've got to reduce your caloric intake by 10, 20 or even 30 percent.

However, women should never try CR during pregnancy, and CR is not for children. Also, never reduce calories to 50 percent of normal intake.

Won't smaller portions mean constant hunger? Not for long. Those practicing CR, including 78-year-old Walford, report that hunger stops a few weeks into the program. Eventually, most people find it difficult to exceed the new calorie limit.

But does CR diminish energy and alertness?

From mice to humans, tests show that the extra CR life span is comprised of prolonged youth, not simply additional time spent crippled, achy or senile. In a host of studies, calorie-restricted animals--and humans--have been shown to be physically, sexually and mentally active for much longer, and they need less sleep. CR also delays age-related immune dysfunction.

Diseases such as heart disease, stroke, cancer, diabetes, osteoporosis and Alzheimer's are either avoided or forestalled.

People who lack the will to exercise might find CR a more forgiving alternative. Work by John Holloszy, MD, of Washington University in St. Louis, suggests that those on a calorie-limited diet actually benefit from not exercising. Studies indicate that the average and maximum life spans--arranged from longest to shortest--are: sedentary CR (longest-lived); active CR; active non-CR; and sedentary non-CR (shortest-lived).

For centuries, humans have fantasized about a fountain of youth, becoming cynical in the process. But for those eager to postpone the daily ravages of aging, a scientifically sound fountain of youth appears to have been near at hand all along--and deceptively simple at that: smaller portions.

Better Nutrition, Dec, 2002 by Michael Downey