Telling the world that all a person has to do to lose weight is eat less or work more, because it’s just basic physics is a mistake. It is a mistake because it makes the person who that doesn’t work for look like they aren’t trying hard enough to lose weight. It is a mistake because the person who is making that claim doesn’t know if that is true. Even though it makes a certain kind of elementary sense, they don’t know whether or not people gain fat because of how MUCH they eat or how little they work.
I know that they don’t know, because it turns out the the highest percentages of obese people throughout history have always been found in poor communities. This has been true even back when just about all work was hard physical work, back when the hardest, most physical work was being done by the poorest people. We all know people who try very hard to lose weight, starving themselves for months, and then when their weight is down and they are done with the diet, they go back to not starving and the weight comes back. Nobody should have to live on starvation rations to stay thin. Nobody can.
In 2007, Jeffrey Flier, dean of Harvard Medical School and his wife and colleague in obesity research, Terry Maratos-Flier, published an article in Scientific American called “What Fuels Fat.” In it, they described the intimate link between appetite and energy expenditure, making clear that they are not simply variables that an individual can consciously decide to change with the only effect being that his or her fat tissue will get smaller or larger to compensate. An animal whose food is suddenly restricted tends to reduce its energy expenditure both by being less active and by slowing energy use in cells, thereby limiting weight loss. It also experiences increased hunger so that once the restriction ends, it will eat more than its prior norm until the earlier weight is attained. What the Fliers accomplished in just two sentences is to explain why a hundred years of intuitively obvious dietary advice— eat less— doesn’t work in animals. If we restrict the amount of food an animal can eat (we can’t just tell it to eat less, we have to give it no choice), not only does it get hungry, but it actually expends less energy. Its metabolic rate slows down. Its cells burn less energy (because they have less energy to burn).
Nobody should look at a person who is carrying a lot of extra weight and think that they are guilty of sloth or gluttony, because so many people are like that now. Two thirds of Americans are now overweight and half of the overweight are obese. There has been an explosion of obesity and it can’t be because there has been an explosion in gluttony. It can’t be that all of a sudden we all need to overeat, that we have all lost control of our ability to regulate our most basic urge–to feed ourselves.
Why is it that obesity is so rarely, if ever, cured by what should be the simple act of eating less? If we suggest as an answer that fat people respond to food restriction just as fat animals do— they reduce their energy expenditure, while experiencing increased hunger (as Jeff Flier and Terry Maratos-Flier explained in Scientific American)—then we’ve opened up the possibility that the same physiologic mechanism that drives obese individuals to hold on to their fat in the face of semi-starvation might have been the cause of their obesity in the first place. Again, that’s not allowed. So instead we blame the failure of the diet on the failure of the fat person to stay on it. It’s a failure of will, a lack of the necessary strength of character to do what lean people do and eat in moderation.
What if the cure for obesity and overweight is not eating less? What if counting calories doesn’t work, because what matters isn’t how many but what kinds of calorie sources they are eating? What if dieting doesn’t work because starvation makes you conserve energy? Well, the cure for obesity does not lie in reducing the number of calories you eat to a number less than the number of calories that you burn. A calorie of sugar is not the same at all as a calorie of meat to your body. America is not fat because of how much we eat, it is because of what we eat.
To be continued…