By Sally Squires
Tuesday, September 4, 2007
Alcohol, nicotine and cocaine are a few of the substances known to be addictive. Now some scientists wonder whether food should be added to the list.
"Are there certain things in food that act on the brain and set up a classic addictive process, like tolerance, withdrawal and craving?" asks psychologist Kelly Brownell, who organized a recent scientific meeting on food addiction at Yale University. While the research is still scanty, the evidence that exists "is extremely interesting and provocative, and suggests to me that something is there," Brownell says.
That's not news to the many Lean Plate Club members who recently e-mailed me about their own food struggles. Most asked not to be named, reflecting the sense that they feel stigmatized by behaviors they have trouble controlling.
"I feel addicted to food at times," one wrote. "Food is like a drug to me. It can change my emotional state. For many years, I have 'used' food as a feel-good panacea, self-medicating with warm chocolate chip cookies or a pint of Chunky Monkey. I will sit down with a food I like in an upset state of mind and will eat it all immediately, beyond the feeling of fullness. It's like a compulsion to finish the entire thing."
Another member described craving sweet foods that leave her feeling moody and unsatisfied. "I need a sugary treat to get me going -- and the worst part is, I can't seem to stop myself at a moderate amount," she wrote. "So I either indulge and then feel guilty or deprive myself entirely and feel sad."
"Thinking about food is like a pounding obsession -- a hammer beating in my head that is driving no nail," another wrote. "The obsession pulses with my heartbeat, but much more intensely. I hate food. I hate feeling full. I'm not in control and I hate letting this demon take over me. I want to stop and nobody has any idea."
Those descriptions certainly sound like the feelings doctors associate with addiction. But whether they stem from the same physiological changes that occur with drug and alcohol dependency is not yet known. "Is it an addiction to food or an addiction to eating?" asks Susan Yanovski, director of the obesity and eating disorders program at the National Institute of Diabetes and Digestive and Kidney Diseases. "Or is it another manifestation of a compulsive behavior like gambling or shopping?"
Brain imaging may soon provide answers. At Brookhaven National Laboratory, psychiatrist Nora D. Volkow and her colleagues map receptors on brain cells for dopamine. This powerful neurotransmitter plays a key role in addiction. Dopamine systems in the brain are disrupted by addictive drugs, from alcohol to methamphetamine, which hijack the control of volition and the brain's quest for rewards.
It turns out that food also affects the brain's dopamine systems. When Volkow, who is also director of the National Institute on Drug Abuse, and her colleagues compared brain images of methamphetamine users with obese people, they found both groups had significantly fewer dopamine receptors than healthy people. Even more interesting: The higher the body mass index, the fewer the dopamine receptors -- a finding that may open the door to a better understanding of why it is so difficult for some people to lose weight and keep it off.
What role dopamine may play in obesity -- and how eating affects it -- is still to be determined. No one knows when the obese people in the study lost their dopamine receptors in the brain or if that loss could be reversed with weight loss. Are some people more susceptible to the effects of eating sugary, high-fat fare because they start out with lower levels of dopamine receptors in the brain? Or could eating those foods decrease dopamine receptors? Might food additives, preservatives and other substances also have an effect on dopamine receptors?
"It's a fascinating topic, but I don't think that it's ready for prime time in terms of suggesting intervention or suggesting that this [food addiction] is a real phenomenon," Yanovski says.
Even if food sometimes prompts feelings and behaviors that resemble addiction, there are likely to be many challenges ahead in how to treat them. Abstinence, the standard treatment for drug and alcohol addiction, won't work for food addiction. "You can be totally abstinent in using drugs or alcohol, but you can't be abstinent with eating," Yanovski notes.
That's why people who feel they've been snared by food addictions sometimes try to eliminate the specific foods that seem to trigger their overeating.
"My name is Lisa and I am a compulsive eater," wrote one Lean Plate Club member who participates in a 12-step meeting for people with eating disorders. "I am addicted to food, and for me, to attempt to eat certain foods in moderation is no different than suggesting that a crack addict or alcoholic smoke crack or drink alcohol in moderation. It simply is not possible."
But by eliminating refined, processed foods high in sugar and white flour, as well as fast foods, artificial sweeteners and food additives, Lisa has shed 30 pounds and has kept it off for the past 4 1/2 years. "For 'normal' people, this may be a non-issue," she wrote, reflecting her belief that she suffers from an illness.
Other Lean Plate Club members say they have learned to view chronic overeating as a symptom of a bigger problem. "Compulsive eating to me is a sign that my soul is hungry for something else," wrote one. "I try to think of it as a sign that I need to change something in my life. When I think of it as a tool for self-knowledge, it becomes a gift and much more manageable.
"I'm still overweight," she notes, "but I'm much lighter!"
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