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Neither feast nor famine

August 16, 2009 12:41 am

"CALORIE-COUNTING Monkeys Live Longer," shouted the headlines describing science experiments last month. Some researchers claim that if humans went on similar diets, with 30 percent fewer calories, we'd all live to be over 100 and avoid many diseases.

But is calorie restriction really the fountain of youth? No matter how much scientists study half-starved monkeys, rats, worms and other hapless lab animals, I don't think this is a realistic or good idea for human beings.

First of all, there are no long-term studies in human beings. What studies we do have on the short-term effects of starvation in humans were brought to us courtesy of the Nazis, who starved and tortured millions of people and took cold-hearted notes.

We also have observations of people suffering from anorexia nervosa, a mental illness in which people starve themselves, sometimes to the point of death.

We know that malnutrition, whatever the cause, makes people feel tired, cold and lightheaded. People's muscles weaken, teeth loosen, and their bones break easily--I've heard of 30-year-olds with broken hips. Starved people also become infertile and lose interest in sex--again, I have seen this in young people with anorexia.

Women who restrict calories after becoming pregnant have babies who are more likely to develop heart disease when they grow old.

Starvation weakens white blood cells, the vanguard of the immune system, making people more vulnerable to infections. Lack of food depresses moods. People also become irritable. And they perform poorly on memory tests, perhaps because they are fixated on their constant, gnawing hunger.

WIRED TO EAT

People who promote caloric restriction say they don't promote starvation or being underweight, just consuming 30 percent fewer calories. So instead of meeting a typical person's needs of 2,000 calories a day, they would restrict calories to about 1,400. They even suggest vitamin and mineral supplements. It sounds benign.

But I say we need long-term studies of calorie restriction in people--and there's a reason we don't have long-term studies, even of milder caloric restriction. That's because most humans cannot stay on diets.

If you've ever tried one, you know the desperate feelings diets spark.

Diets fail to produce long-term weight loss for all but a tiny number of people. (By long-term, I mean for more than five years.) Most people regain even more weight than they lost, according to several major studies, including the Health Professionals Follow-up study.

Our very biology fights diets--our bodies are wired to prevent starvation.

People who succeed at restraining their eating have been shown to have lower metabolic rates--they burn fewer calories sitting still. This is the opposite of what dieters want, and it's the body's way of fighting back against the restrictions.

Also, studies show that restrained eaters are more likely to binge in response to stress. Restrained eating is a bad thing.

ANOTHER WAY

Don't get me wrong: I'm not saying that most of us couldn't afford to be more moderate in our eating. Overeating is an epidemic in America. Studies show we eat hundreds more calories a day than our great-great-grandparents did at the turn of the previous century.

And we're less fit than our great-grandparents were. They had to chop wood and carry water just to survive, while many modern Americans don't lift anything heavier than the remote control.

One modern society often praised for its longevity and healthy eating is Okinawa. "The Okinawans, the longest-lived people on Earth, consume 40 percent fewer calories than the Americans and live only four years longer," according to Australian researchers.

Granted, many Americans overeat, so you could argue that the Okinawans are not truly restricting calories--they're probably just eating appropriate amounts. I have read that in Okinawa, people enjoy eating until they feel about 80 percent full. Then after a meal, as the food takes time to digest, they feel 100 percent full and satisfied.

In any case, a severely calorie-restricted diet--the kind that cuts calories by 30 percent or more--is another thing altogether. It's neither easy nor pleasant.

A recent study in Louisiana showed that people on severely restricted diets had less energy to walk around or do other daily activities.

Who wants to live longer if you have to feel tired and weak and lose interest in sex? I'm not even mentioning being deprived of chocolate!

My point here is that it may not be worth sacrificing quality of life for quantity.

THE MIDDLE GROUND

Why must life be all or nothing, feast or famine? I choose the middle ground. Just four healthy habits can add 14 years to your life, according to a British study:

Exercising for 30 minutes daily.

Limiting alcohol to one drink a day.

Eating five servings of fruits and vegetables a day.

Not smoking.

Other quick things proven to extend our lives are common sense: brush and floss your teeth, get vaccinated, get checkups, wear a seat belt (and a helmet while bike-riding), wash your hands, and install a smoke detector in your home.

Folks who have more connections to other people live longer, too, studies show. So instead of holing up and starving yourself in the name of longevity, consider inviting friends or family over. You might grill a healthy dinner, and eat until everyone is satisfied. Afterward, take a walk in the summer twilight, count fireflies or stars, tell stories, and share some laughter. Live!

Jennifer Motl welcomes reader questions via her Web site, brighteating.com, or mailed to Nutrition, The Free Lance-Star, 616 Amelia St., Fredericksburg, Va. 22401.