Medical Examiner

Is Calorie Restriction Really Different From Anorexia?

Forget everything you’ve ever heard about anorexia. It turns out starving yourself is healthy.

So, at least, one might conclude from recent articles (here, here, and here) about calorie restriction, which studies have shown to extend the lives of animals like monkeys and mice and which is now being tested with humans. The mechanism by which calorie restriction slows aging in animals isn’t yet understood. But it seems to depend on these basic mechanics: When you eat less than you need, your metabolism slows down. Your heart rate ebbs, your temperature drops. It’s an evolutionary response meant to help us survive during famines (and it explains why some dieters have such difficulty losing weight).

As a former anorexic, I’ve found it strange to hear scientists hail low metabolism—a central feature of that disease—as a sign of health and potential longevity. When I was being treated, my doctors invoked my low metabolism as a catchall for the physical damage I was doing. My low heart rate, amenorrhea (the loss of my period), and the goose bumps I got in 70-degree weather were all signs of illness. So, how can something that is a symptom of disease in one person be a marker of good health in another?

This isn’t a theoretical question. Although we don’t know yet whether the longevity benefits extend to humans, a number of people—probably at least several hundred—have put themselves on draconian diets in the hope of living longer. They refer to their regimen as CR (calorie restriction) or CRON (calorie restriction with optimal nutrition), and they call themselves CRONies. They eat obsessively, measure every calorie, and lose huge amounts of weight. Except for the fact that most of them are men, they look a lot like anorexics. And, on closer examination, it turns out they are a lot like anorexics. Many are trying to jolt themselves out of a midlife crisis, much as many anorexics are seeking relief from adolescent unhappiness. Like anorexics, CRONies discover in starvation an apparent solution to their problems: a source of energy (at least at first), a sense of purpose, and relief from stress.

Remarkably, no one from the eating disorders field has stepped forward to explain what the difference between calorie restriction and anorexia might be. None of the major organizations—the Academy for Eating Disorders, the National Eating Disorders Association, and the Eating Disorders Coalition—has made any statement on calorie restriction. I suspect they don’t really know what to say. Doctors I’ve interviewed say they’re concerned about the message that semistarvation is healthy. But, when pressed to say whether reducing one’s metabolism is overall healthful or harmful, they admit that we simply don’t know. One doctor admitted that there may be benefits to anorexia, assuming you survive it: There is evidence, for instance, that women who recover from anorexia are at lower risk for cardiovascular disease later in life. On the other hand, one risk of long-term calorie restriction (and anorexia) is bone loss, which if severe enough causes osteoporosis. (When your metabolism slows down, the levels of hormones that trigger your body to add calcium to your bones also decrease.)

Proponents of calorie restriction are much more assertive in differentiating CR from anorexia. The Web site of the Calorie Restriction Society, an organization that claims more than 2,000 members, has a page dedicated to listing the differences. It states, “Anorexia: It’s All About Appearance. Calorie Restriction: It’s All About Health.” The next point is that anorexia is the result of low self-esteem (“Anorexia: I Am Bad”), whereas CR is about loving and respecting yourself: “The inner monologue of a CR practitioner is ‘Calorie Restriction is worth the effort because it may prolong my life and health.’ “

While these distinctions have some superficial truth, they rely on an extreme oversimplification of anorexia, and of CR, as well. To begin with, anorexia is not all about appearance. An anorexic, like a CR practitioner, could easily be motivated by the belief that what she is doing—watching her portions, avoiding “bad-for-you” foods—is healthy.

More importantly, once someone has been restricting food for a certain amount of time, she discovers advantages, not appearance-related, in the way that her mind and body respond to starvation. After this point, the anorexic is motivated by a cost-benefit analysis that sounds very much like the calorie restrictor’s: “This is worth the effort/pain/fighting with my parents, because of X benefit.” In my case, there were several noticeable pluses. Being hungry gave me energy. It helped me focus on my work. It made me feel emotional and creative in a way that I enjoyed. At the time, in fact, I believed I was eating as I did much more for the intellectual and creative edge it gave me than to look thin.

Now I understand what happened better: My starvation triggered the release of endorphins. In evolutionary terms, this is designed to give humans heightened coping powers in an emergency. In my case, it gave me a sense of well-being and made me feel sharp and energetic. This feeling became an addiction, so that I pursued it even as my tolerance level rose and the same amount of endorphins no longer produced the same effect, at which point I became quite depressed.

The same thing happens in people who practice CR seriously. Your body doesn’t know whether you’re eating only two-thirds of a normal caloric intake in order to lose weight, or to live forever, or because the crops have failed or the antelope died out. And I’d argue that a lot of CRONies are susceptible to the addictive nature of starvation, because they begin CR out of a sense of dissatisfaction with their lives.

How do I know? Because to write about this, I joined the Calorie Restriction Society, browsed the archives of their e-mail list, and interviewed several CRONies. Tomorrow, I’ll explain how my interviews led me to conclude that calorie restriction, while not anorexia, constitutes its own new kind of eating disorder.