The Man Who Ate Everything - Jeffrey Steingarten [64]
The difference is important because hunger and appetite do not always coincide. I don’t feel hungry after the main course of my dinner, but I still have an appetite for dessert. Eating lots of fiber may take away my hunger and make me feel full, but as we’ll see, it may not do much to appease my appetite—my tendency to eat. There are chemicals that affect one and not the other. The drug naloxone can reduce the amount you eat without alleviating your hunger; dopamine antagonists do the reverse.
Someday medical science may discover a way to transform me into one of those people who can eat as much as they wish and never gain weight. But until it does, I plan to concentrate on trying to calm my appetite. I don’t want to eat differently, just to eat less. Not for me a diet of steamed broccoli spears with toasted sesame seeds. And as luck would have it, today’s research on appetite is as enterprising and energetic as any specialty in the study of obesity. I’ve located four hundred papers and abstracts published in the past three years alone.
My current thinking is that if I can only get my hands on 180,000 pounds of raw potatoes, everything will turn out right. As it may take me a while to explain how I arrived at this conclusion, I should first summarize some current findings about appetite that may be helpful in a minor sort of way.
• Protein is more satisfying, calorie for calorie, than carbohydrates. A high-protein diet fed to rhesus monkeys reduced their intake by 25 percent. A high-protein lunch caused human subjects to eat 12 percent less at dinner than a high-carbohydrate lunch. This is bad news for nutritionists, both in government and on best-seller lists, who urge us to emphasize pasta, grains, and beans.
Unfortunately, nature often insists on putting protein and fat in the same package, like cows and chickens. Eating stringy low-fat beef or chicken without its crispy skin holds little gastronomic interest, but high-protein lean fish and tofu, the mainstays of the Japanese diet, are another matter entirely. I lost five pounds on a recent culinary idyll in Japan, and two months later I have not gained them back. Could this be the solution to everything?
• Solid foods are more satisfying than liquid foods with the same caloric content. It’s conceivable that the mere activity of chewing helps appease your appetite or that solid food stays in your stomach longer and makes you feel fuller. But both possibilities have been ruled out in the laboratory, leaving us without an explanation for this phenomenon.
• Filling up with fiber does not appear to help much with your appetite. Adding fiber to a very low calorie diet makes you feel less hungry at the end of the meal, but it does not seem to affect how fast your appetite returns afterward. And though a high-fiber breakfast makes you feel fuller than a low-fiber breakfast with the same number of calories, it will have only a slight or short-lived effect on the amount you eat at lunch, depending on which study you read.
This surprised me. I used to think that if I could only work up an interest in those dreary yet bulky high-fiber, low-calorie foods, my appetite problem would be solved. One extreme measure sometimes used to help massively obese people is to place a balloon in their stomachs and fill it up with air or water. The idea is that a gastric balloon—like great quantities of fiber-rich food—will suppress their appetites by triggering “stretch receptors” in the walls of their stomach and intestines, sending signals of fullness to the brain. But gastric balloons are often unsuccessful, and when they work at all, patients feel less hungry and eat less food for only a few weeks and then return to normal. As we’ll see later, the messages the brain receives in the course of a meal are so numerous and complex that gastric distension has only a weak effect on lessening your appetite once the body learns that you are not eating your usual number of calories.
• Low-calorie snacks will stave off your appetite for the first