Most people overeat from time to time, and many people believe they frequently eat more than they should. Eating large amounts of food, however, does not mean that a person has binge eating disorder. Most people with serious binge eating problems have some of the following symptoms:
Frequent episodes of eating what others would consider an abnormally large amount of food
Frequent feelings of being unable to control what or how much is being eaten
Eating much more rapidly than usual
Kessler stops short of calling Americans' love for sugary, fatty foods a "food addiction." But he believes there are similarities between why some people abuse drugs and why some of us can't resist every last deep-fried chip on a heaped plate of cheese-smothered nachos.
Knowing what's driving our overeating behavior is the first step to changing it, he says.
"For some, it's alcohol," Kessler tells WebMD. "For some, it's drugs. For some, it's gambling. For many of us, it's food."
Kessler, a Harvard-trained pediatrician and medical school professor at the University of California, San Francisco, started researching what would become The End of Overeating after watching an overweight woman talk about obsessive eating habits on The Oprah Winfrey Show. It sounded familiar. Kessler's own weight has zoomed up and down over the years, leaving him with suits of every size.
"For much of my life, sugar, fat, and salt held remarkable sway over my behavior," he writes.
And so the man who tackled tobacco companies while leading the FDA started researching why he couldn't turn down a chocolate chip cookie. He pored over studies on taste preferences, eating habits, and brain activity, conducted studies, and talked to food industry insiders, scientists, and people who struggled with overeating.
His theory: "Hyperpalatable" foods -- those loaded with fat, sugar, and salt -- stimulate the senses and provide a reward that leads many people to eat more to repeat the experience.
"I think the evidence is emerging, and the body of evidence is pretty significant," Kessler says.
He calls it conditioned hypereating, and here's how he says it works. When someone consumes a sugary, fatty food they enjoy, it stimulates endorphins, chemicals in the brain that signal a pleasurable experience. Those chemicals stimulate us to eat more of that type of food -- and also calm us down and make us feel good.
The brain also releases dopamine, which motivates us to pursue more of that food. And cues steer us back to it, too: the sight of the food, a road lined with familiar restaurants, perhaps a vending machine that sells a favorite candy bar. The food becomes a habit. We don't realize why we're eating it and why we can't control our appetite for it.
Once the food becomes a habit, it may not offer the same satisfaction. We look for foods higher in fat and sugar to bring back the thrill.
Kessler points to these factors as the cause of a dramatic spike in the number of overweight Americans in the past three decades.