Quick – how many people do you know who are too heavy? And how many do you know who aren’t? Chances are, you know more overweight people than thin ones, since normal weight people are now in the minority. Two-thirds of US adults are either overweight or obese. How we got this way has been endlessly discussed. We eat too much of the wrong foods, we eat all the time and we don’t exercise enough to lose weight. So, given what we eat and how little we move, the real question is “Why isn’t everyone fat?”
Humans are designed to stockpile calories. We’re genetically programmed, just like our ancient hunter-gatherer ancestors were, to hang on to every calorie we can. These thrifty genes can work against us by helping us to store more. The wide availability of cheap, tasty food just makes it even easier to do so. But there’s a bit of genetic programming that determines how much energy we spend every day, too—even influencing how much we move when we’re not exercising.
We all know people who to eat a fair amount and never seem to gain. Chances are, many of them make healthy, relatively low-calorie selections naturally. But the other thing that many of them do is to simply burn more calories—not through exercise, but through something called Non-Exercise Activity Thermogenesis, or more simply, NEAT.
It boils down to this: NEAT people move around a lot more than other people during the day. You know the ones. They can’t sit still. They jiggle their legs, they talk with their hands, they drum their fingers. They fidget more, or get up from their desks frequently during the day to stretch or walk down the hall to talk to a colleague instead of e-mailing.
A few years ago, scientists studied the NEAT phenomenon in normal and obese volunteers. Using technology that was invented for fighter jet control panels, their subjects slipped into something special – underwear with embedded sensors that recorded their every movement every half-second, 24 hours a day, for 10 days. In the end, they determined that the heavy people sat for about 2.5 hours longer every day than the lean people—who stood, moved and walked more and burned an extra 350 calories each day in the process.
Next time you’re in a public place, say a coffeehouse, become an observer. You may notice that heavier people sit very still and hardly move, while leaner people may use more hand gestures, or wiggle a foot or swing a crossed leg. NEAT isn’t the entire answer to the obesity problem, but it does help explain why some people don’t gain as easily as others. Fidgeting and moving around enough to burn an extra 350 calories a day is no “small potato.” It’s like jumping rope nonstop for a half an hour.