The Man Who Ate Everything - Jeffrey Steingarten [65]
• The taste of sweetness in itself, with or without calories, has been widely found to stimulate the appetite; many manufacturers sweeten their packaged foods to make you eat more of them. In one experiment, people were given either a plain yogurt or an artificially sweetened yogurt before lunch; those who ate the sweetened yogurt were hungrier at lunch (and consumed more) than those who ate the plain one.
A cookie or a candy bar between meals—maybe even a piece of fruit—seems a prescription for overeating later. If you offer laboratory animals a sugary snack in addition to their regular diet, they will overeat by 20 percent; when the same sugar is put into their food, their appetite and intake become self-regulating again. This works with nearly every type of sugar, even those that don’t taste sweet, like dextrin. Fructose seems to excite your appetite less powerfully than other forms of sugar, but only if you don’t eat it with other carbohydrates such as bread or muffins.
Artificial sweeteners have been inconsistently reported to stimulate the appetite for anything that follows, to incite a craving for sugar, to satisfy your need for something sweet, or to have no effect at all. The general feeling is that while sugar stimulates your appetite and then satisfies it with calories, noncaloric sweeteners stimulate your appetite but leave you hungrier for other foods. Still, you will probably take in fewer calories from these other foods than the calories you saved by not eating sugar.
Recently all of this was thrown into question by a study of sweetened and unsweetened cereals. The sweet taste alone was not found to increase food intake for the rest of the day. But subjects who knew that their cereal was sweetened with aspartame (NutraSweet’s artificial sweetener) ate more than subjects who didn’t know. They were apparently so reassured by having eaten a lower-calorie breakfast that they ended up consuming slightly more calories overall than those whose cereal had been sweetened with sugar.
Aspartame may have an advantage over other artificial sweeteners. People given doses of aspartame in capsules (so that they would not taste its sweetness) ate less later, probably because aspartame changes the profile of amino acids in the blood. Aspartame might act as a mild appetite suppressant if it weren’t so sweet.
• Exercise suppresses your appetite only briefly and only if the exercise is intense. Astoundingly, there are no conclusive answers on the question of exercise and appetite. The good news is that exercise does help you lose weight. Theoretically, you should eat more after a workout rather than less because your body, trying to make up for the calories you have burned, will temporarily set your metabolic rate to a higher level. But at least in the short term, exercise does not appear to increase your appetite, especially if you are overweight, and it does burn calories.
• Two kinds of diets are guaranteed to increase your appetite: a high-fat diet and what is known in the laboratory as a cafeteria diet. Either of them causes lean animals who ordinarily have no problem regulating their intake of food and their body weight to eat more than they should. Most studies agree that dietary fat appeases your appetite less effectively than either protein or carbohydrates. In one experiment, human subjects who were given as much low-fat food as they wished consumed 11 percent less than they usually did; offered a high-fat diet, they ate 15 percent more than normal. I would love to explain the difference by pointing out that high-fat food simply tastes better. But experiments in which distasteful fats such as margarine were added to soups yielded the same result.
A cafeteria diet consists of a wide variety of palatable foods. Experimental animals fed a bland, balanced diet known as laboratory chow typically