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David Kessler: Fat, Salt and Sugar Alter Brain Chemistry, Make Us Eat Junk Food

Paulette says that she was not taken aback when her husband of 34 years would disappear in the middle of the night on his dumpster tour. "Nothing surprises me anymore," she said. "When he wants to find something out, there's really no stopping him."

Through interviews with scientists, psychologists and food industry insiders, and his own scientific studies and hours spent surreptitiously watching other diners at food courts and restaurants around the country, Kessler said, he finally began to understand why he couldn't control his eating.

"Highly palatable" foods -- those containing fat, sugar and salt -- stimulate the brain to release dopamine, the neurotransmitter associated with the pleasure center, he found. In time, the brain gets wired so that dopamine pathways light up at the mere suggestion of the food, such as driving past a fast-food restaurant, and the urge to eat the food grows insistent. Once the food is eaten, the brain releases opioids, which bring emotional relief. Together, dopamine and opioids create a pathway that can activate every time a person is reminded about the particular food. This happens regardless of whether the person is hungry.

Not everyone is vulnerable to "conditioned overeating" -- Kessler estimates that about 15 percent of the population is not affected and says more research is needed to understand what makes them immune.

But for those like Kessler, the key to stopping the cycle is to rewire the brain's response to food -- not easy in a culture where unhealthy food and snacks are cheap and plentiful, portions are huge and consumers are bombarded by advertising that links these foods to fun and good times, he said.

Deprivation only heightens the way the brain values the food, which is why dieting doesn't work, he said.

What's needed is a perceptual shift, Kessler said. "We did this with cigarettes," he said. "It used to be sexy and glamorous but now people look at it and say, 'That's not my friend, that's not something I want.' We need to make a cognitive shift as a country and change the way we look at food. Instead of viewing that huge plate of nachos and fries as a guilty pleasure, we have to . . . look at it and say, 'That's not going to make me feel good. In fact, that's disgusting.' "

Kessler said he's made that shift in his own life, eating small portions of foods that contain fat, salt and sugar, part of a "food rehab" plan he suggests in the book. He has certain rules -- no french fries, ever -- that help him navigate through vulnerable moments.

He has embraced spinning -- the first time he has regularly exercised. "I hated physical activity, all of my life, mostly because I was fat and it was hard to do," he said. "But I just wanted to do something. I picked spinning because you can't fall off the bike." He worked with a private trainer for weeks just to be ready to take a class. "I was embarrassed to go into the class," he said.

Now Kessler tries to spin every day and belongs to multiple health clubs so that he has more options for class times.

He avoids the cues that focus his brain on "highly palatable" foods, going so far as to chart a different route through San Francisco International Airport so that he doesn't walk past the fried dumpling stand.

Kessler's weight is relatively stable at 162 pounds. But there's something else that's changed. As he has come to better understand himself, the food cravings and the resulting anguish he felt have subsided.

"So I'm at peace," he said. "After 30 years, I'm at peace."


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