The Man Who Ate Everything - Jeffrey Steingarten [63]
In our defense, I should mention that modern science has shown chubby people to be more discriminating and discerning than our skinny neighbors, at least at the dinner table. If you take away their food for twenty-four hours, skinny people will breathlessly devour whatever you put in front of them. We, in contrast, will still pick and choose, eating only food we normally enjoy and rejecting what we normally find distasteful. One reason for this is that chubby eaters are rarely truly hungry. We simply have abnormally generous appetites. But let’s leave the distinction between hunger and appetite until later.
Obesity is partly—maybe largely—a genetic condition. Australian research has found you can predict whether a male adolescent will become overweight by learning whether his father is. Any diet doctor can tell you about patients who weigh seventy-five pounds too much, eat only a thousand calories a day, and don’t lose an ounce. In a study using volunteers from a Vermont prison, men of normal weight consumed twice their regular intake of food, as many as seven thousand calories a day. Some didn’t gain a pound; some gained only a few. We all know people like that.
I am cursed with thrifty genes. This sounds like a fine thing, and for about a million years it was. In a triumph of natural selection, my remote ancestors evolved the talent of turning food into energy with extreme efficiency, saving lots of fuel to store as fat for a rainy day, when people with wasteful genes find themselves in a real pickle. The problem is that rainy days are much less common now than they were a million years ago. I, for one, spend only brief periods more than an arm’s length from an abundant supply of inviting food.
Always on the lookout for a scapegoat, I have had my metabolism tested as often as possible since boyhood. Every attempt was a total flop. The doctor makes you lie down and breathe through a tube attached to a machine that measures how much oxygen you inhale. People with a low metabolic rate use up less oxygen because they oxidize (or burn) fewer calories every hour. But research in the past two decades has discovered that most chubby people burn just as much energy as they should—given their height, weight, and physical activity. Attempts to tinker with the process are rarely successful. If you take a thyroid hormone to raise your metabolic rate, your appetite is likely to become voracious. The same thing happens when you take drugs that block the burning of sugars and fats from today’s lunch or dinner in order to force your body to draw on the fuel it stored long ago in your fat cells. These drugs help you lose weight only if you can ignore your hunger and stick to a strict dietary regime. Appetite is still the enemy.
Hunger and appetite are not the same, at least as scientists use the terms. You probably don’t feel hungry while you are making elaborate plans for a week of intensive eating in Paris, but your plans themselves are an expression of boundless appetite. Hunger is an annoying, nagging sensation that triggers constant thoughts of food and reminds you that your body wants to eat. But appetite is a more objective measure. Appetite is simply the tendency to eat. It is difficult to measure somebody else’s hunger except by asking him how he feels, but we can gauge the size of his appetite by counting up how much he actually ate. Satiety is the state of being