Lemondrop

Calorie counting sucks. It's bad enough doing it for a few days before a wedding or something -- but could you imagine counting calories everyday for the rest of your life?

That's what "calorie restrictors" do. Calorie restriction (CR) is a lifestyle, not a diet, that involves cutting calorie intake drastically to improve health and longevity. Those who do it say they feel great -- and thin. But is it healthy?

The Science Behind It

CR slows metabolic rates and forces the body to conserve energy in efforts to maintain its mass on less food. For reasons scientists are still unsure of, this can help people and animals live longer.

Cornell University researchers were the first to study CR in the 1930s, when they found it could lengthen the lives of mice and rats. A University of Wisconsin study on rhesus monkeys begun in 1989 showed that those on restricted diets were healthier and more energetic than the normal-weight primates who ate regularly.

CR cuts daily calories by about 30 percent -- so if you're used to eating 1,700 calories, you'd eat just under 1,200 -- and often requires you to keep a food journal. The most fervent CR practitioners are among the 3,000-member Calorie Restriction Society (CRS), which is "dedicated to understanding and promoting the Calorie Restriction diet."

Today, the National Institutes of Health is conducting a clinical trial on CR called Calerie, which stands for Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy. Doctors are working with 132 men and women to see if reducing their daily calories by 25 percent for two years affects the aging process and diseases.

Raw Food and CR

Acupuncturist Susan Schenck, LAc, author of "The Live Food Factor: The Comprehensive Guide to the Ultimate Diet for Body, Mind, Spirit and Planet," has practiced a raw diet for years and CR for the last few months. She consumes 1,400 to 1,500 calories a day and doesn't eat after 6 p.m. She's lost weight and says she feels happier and more energized.

"I'm sitting down and eating more consciously and enjoying food more," says Schenck, 53, of San Diego. In her past diet life, she ate microwave food and canned veggies. Now she eats smoothies with fiber, kale, lettuce, ginger and lemon juice. Interestingly, Schenck was also anorexic and bulimic as a teen and young adult, but said CR doesn't trigger her old behaviors because she's focused on nutrition versus thinness.

Experts Weigh In

Among the experts we spoke about CR with, one supports it, one shuns it, and one is on the fence.

New York City cardiologist Dr. Nieca Goldberg, author of "Dr. Nieca Goldberg's Complete Guide to Women's Health," does not recommend CR, saying it sounds "like a chore." She suggests instead a balanced diet of colorful fruits and vegetables and limited sweets, salts and alcohol, and exercise.

"Calorie restriction can only go so far. Exercise is necessary to maintain [weight loss]," she said.

Mary Hartley, RD, MPH, director of nutrition for CalorieCount.com, thinks CR can be healthy if done right, but doesn't recommend it for pregnant women or people who've had eating disorders. What differentiates CR from eating disorders is that the former focuses on nutrition and doesn't hide eating.

"It's not anything that anybody is going to recommend en masse," Hartley said of CR. "You really give up the pleasure of eating. You really do have to make sacrifices and have diligence." She advises against eating less than 15 percent of calorie requirements because it can result in malnutrition The American College of Sports Medicine (ACSM) recommends calorie levels never drop below 1,200 for women.

Sharon Zarabi RD, CDN, CPT, nutrition expert for Focus28 Wellness, says CR "is a complex theory. The more one cuts out calories, the more efficient the body becomes at conserving energy." CR will help with initial weight loss, she said, but over time, exercise will need to be reintroduced.

So CR might help you live till 90 -- but it will be a strict life with few decadent desserts, glasses of wine or pizza slices. Or you can take the gamble and enjoy yourself a little bit. What would you choose?