Friday, April 24, 2009
How Junk Food Works
Ex-FDA chief offers clues to food addiction.
It is a perplexingly common experience: You open a bag of cookies, intending to have one or two. An hour later, the bag is empty, and your self-loathing is at its peak.
But compulsive overeating is not a character flaw, according to David Kessler, former head of the Food and Drug Administration. It is, rather, a “biological challenge.”
Readers may remember Kessler from his anti-cigarette and food product labeling crusades during the Clinton administration. In his forthcoming book, The End of Overeating: Taking Control of the Insatiable American Appetite, Kessler notes that while food took over his brain, the foods in question were not carrots, apples and green leafy vegetables. “Conditioned overeating,” as Kessler dubs it, is driven by a biological drive to eat high-fat, high-sugar foods even when we are not hungry. Moreover, such foods are cheaper than more healthy alternatives.
What Kessler describes in his book is a system of reward-driven eating abetted by a food industry fully aware of the biological attraction exerted by salt, fat, and sugar. Kessler himself is no stranger to this attraction. “I have suits in every size,” Kessler writes, according to a report by Lauren Neergaard for AP. “Once you know what’s driving your behavior, you can put steps in place.”
Kessler has also served as dean of the medical schools at Yale and the University of California at San Francisco. On the book’s Amazon site, Michael Pollan, author of In Defense of Food, calls Kessler’s book “a fascinating account of the science of human appetite, as well as its exploitation by the food industry.”
It is becoming increasingly clear that fat and sugar in combination are capable of producing a dopamine-driven surge of intense pleasure in people with a propensity for addictive behavior. Mice that have been genetic altered so that they lack the ability to taste sweet foods still prefer sugar water to regular water. (See my post on Dopamine and Obesity.) Kessler provides additional evidence that certain forms of overeating qualify as legitimate drug addictions. Just as it is with, say, cocaine addicts, the supersaturated reward pathways of the brain do not have effective mechanisms for signaling: “That’s enough. Stop eating.”
It may seem obvious in retrospect that the same mechanisms that make it so difficult for many drug addicts to “just say no” would also function in the case of addicted overeaters. What happens is similar to the flooding of reward circuitry that occurs in cases of what we might call “compulsive overdrugging,” otherwise known as addiction. The food industry, according to Kessler, has figured out what works, has packaged fat-and-sugar foods in products that scarcely even have to be chewed, and it has priced these products to move.
Yale university conducted studies in which “hypereaters” were given the odor of chocolate during an MRI scan. Normal eaters get used to the odor and habituate rapidly. Hypereaters find that the odor of chocolate becomes more demanding and overpowering with time. And even drinking a complete chocolate milkshake did not quell the craving.
According to Publisher’s Weekly, Kessler’s book, set to be released on April 28, “provides a simple food rehab program to fight back against the [food] industry’s relentless quest for profits while an entire country of people gain weight and get sick.”
Photo Credit: Neurological Correlates