Can Dieting Be a Drug?

Explain this: Most people abhor dieting – it’s just too hard to eat less than the body naturally craves. But a person with anorexia nervosa diets, loses weight and actually feels better. It’s almost like dieting becomes the ultimate accomplishment, a fix that a certain kind of dieter learns to crave.

Sound like an addiction? Maybe, says biologist Valerie Compan at the Centre National de la Recherche Scientifique, Montpellier, France. Last October, she and her colleagues found that starvation in mice activated some of the same brain pathways as the highly-addictive club-drug Ecstasy.

Here are the details: When Compan injected Ecstasy into rodents, they acted like anorexics: When offered food, mice didn’t eat much and, when food was withheld, they did not work to get it. The same effect occurred when Compan injected a compound that stimulated a receptor for the neurotransmitter serotonin (called 5-hydroxytryptamine 4 or 5-HT4).

The finding is intriguing because serotonin is the culprit in all kinds of mood disorders, including depression. At the same time, researchers such as Walter Kaye, at the University of San Diego, have linked problems with the serotonin system to anorexia and bulimia. Finally, some individuals with bulimia respond well to drugs that target the serotonin system, including Prozac.

Given this evidence, Compan just added another piece to the eating disordered puzzle by finding that both Ecstasy and her experimental compound target the 5-HT4 receptor. What’s more, the receptor initiates a series of chemical events that leads to the production of another neurotransmitter important in drug addiction, CART (for cocaine and amphetamine regulated transcript). CART causes a cascade of molecular changes that damp down appetite in a brain structure called the nucleus accumbens, which is involved in reward.

With that “R-word” we get the link to addiction. Almost every drug of abuse acts in the nucleus accumbens -- to boost the levels of a neurotransmitter called dopamine, which prompts good feelings in response to certain behaviors. In essence, Compan showed that starvation is connected to the reward system. Stimulating that system prompts a lack of eating. At the same time, starved animals given stimulators of the 5-HT4 receptor ate even less. Thus not eating, under certain conditions of serotonin functioning can actually tap feelings of reward.

“Anorexia can be an addiction,” Compan says, “And it appears to share the same (neural) mechanism as a drug of abuse, Ecstasy.”

For those who suffer, the message is: Be gentle with yourself after a relapse or setback in healing. It’s tough to give up a “drug” that co-opts the intricate workings of our brains. For therapists: take a lesson in addiction to better understand the incredible resistance against which you will battle when trying to help individuals with eating disorders. After all, drugs and addictions are powerful forces.

Comments

[Glenn]

Interesting. I have two questions regarding addiction and eating: If anorexia and bulimia are addictions, is full recovery possible? Is chocolate addictive for binge eaters?

[Trisha Gura]

I'm not a therapist, but the therapists do tell me that full recovery is possible. The question I have had, and that I explored in my book, "Lying in Weight:the Hidden Epidemic of Eating Disorders in Adult Women," is what defines recovery? If the definition is stopping the behaviors such as restriction, bingeing and purging, about a third of those who suffer from eating disorders fully recover. Yet, my personal experience and my conversations with women in my book has led me to believe that even when the behaviors stop, the obsessive thoughts about thinness and body image do linger. Kind of like someone diagnosed with alcoholism who abstains.

Of course, it would be a great tragedy if a person said, "Well, my ED is an addiction, so I guess I'm stuck with it," and not seek treatment. Healing can be an amazing journey, and one I recommend highly. You can live a wonderful and happy life having been diagnosed with an ED. What may linger are the brain changes that spurred the disease in the first place. But you can learn how to deal with those thoughts and obsessions.

As to chocolate ...why don't I deal with that in a future blog? It's a controversial but fascinating topic. TG