Is overeating a psychological disorder?

A little of both, and everybody's different. Some people are certainly born with a dysfunctional appetite. Their nervous system isn't programmed right and doesn't send their brain the "full" signal when they've ingested the correct number of nutrients to support their metabolism.

Other people have problems that might be called behavioral or environmental or any number of things, particularly as children, when they have a reasonable expectation of having their behavior shaped by their elders and the society around them. Many children are stuffed with food as a substitute for other types of care, including love or sheer attention and companionship. Their psychology is slowly rewired and when they grow up the warm feeling the rest of us get from a close friendship or a job well done is, for them, produced by a surfeit of food.

Other children suffer from bombardment with encouragement to eat more (TV commercials, well-meaning friends, and perhaps a little of the parental guilt noted previously), coupled with discouragement to burn off the calories. Many schools are discontinuing recess and even sports programs are shrinking. I absolutely loathed P.E. ("physical education") as a child but after seeing some of the kids now growing up without it, I can't help but consider myself lucky to have endured it.

When talking about adult-onset overeating, some of these factors can still apply. People who grow up into a life they weren't expecting, with dysfunctional relationships, failed university performance or disappointing career opportunities, may gravitate toward food as a substitute just like a child. Adults also expend far fewer calories in their normal daily routine than their predecessors, sitting behind desks, driving everywhere, and even using self-propelled lawnmowers, so it's easy to eat more than they burn.

But there's another factor that deserves more attention, and it's the effect of yo-yo dieting on our caveman's metabolism.

Our Mesolithic ancestors had no way to accumulate a significant surplus of food. They didn't have permanent residences because they were nomads, so all they could possess was what they could carry on their trek--without the technology of wheels or draft animals. As a result, a year of poor rainfall could be a year without enough food.

Their bodies were programmed to avoid dying during a famine. They produced enzymes to increase the efficiency of digestion, reduced the generation of waste heat, slept more, moved more languidly, and adapted to a number of conditions and behaviors that might have adverse consequences in the long run, but were necessary to survive the short run.

Hopefully, next year the rainfall would return, the game would be more plentiful, the intake of nutrients would return to normal, and the metabolism could snap back out of "famine mode."

But what would happen if famines became a routine occurrence? What if every bountiful year were followed by a year of shortage? Their bodies would do the logical thing and remain in "famine mode." During the good years they'd be miserly with the use of calories, so they could store them up for burning during the lean years. After two or three famines, they'd be locked in permanent famine mode.

Well guess what people do to themselves when they go on a crash diet one year, then fall off the wagon and fatten back up the next year, then feel remorseful the next year and lose the weight, then put it back on? They're training their bodies to go into permanent famine mode! They sleep more, they lose their nervous tics, their stool changes consistency.

I know a woman who did that. She lost and regained the same hundred pounds about five times. Today she is trapped into a 1300-calorie daily diet, and even though she works hard and gets plenty of physical exercise, she can barely avoid gaining weight.

The moral of the story is: If you need to lose weight, don't try to lose more than about one pound a month, or you'll trick your body into thinking there's a famine and it has to adapt to more efficient digestion of the calories it receives.

 

That is by no means universal. Many people max out on fat rather quickly, but can eat themselves silly on sugar or starch. It's also a matter of acclimation. Some people who have spent their lives on diets without excessive fat are disgusted or even nauseated by it.

Acclimation can work in unexpected ways. This may be apocryphal but the person who told me about it was a biochemist. About forty years ago when the junk food industry developed some really effective, really cheap preservatives, they immediately started putting them in all their products. It gave them an almost indefinite shelf life, reducing their returns, allowing them to save money on slower shipping, and increasing profits.

But a lot of consumers didn't like the taste of the new product. They had to do some serious testing to figure out what people liked better about the old product. In desperation, one researcher hit on the idea of feeding the test subjects an OLD batch of the old product, one that had already been on the shelf too long. They loved it! It turned out that they had been acclimated to the taste of rancid fat!

So for a couple of years, they had to add artificial rancid flavor to their products, slowly tapering off as people got used to it.

Of course, now we know that the preservative they used was transfatty acids, which are just as bad for us as rancid fat.

 

You know America is a great country when the most widespread nutritional problem among our poor people is obesity.