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Watch out for the portion-size trap. For reasons known only to bureaucrats, the portion sizes provided in the U.S. government's food pyramid can differ dramatically from those indicated on a product's food label. (One set of figures is regulated by the Department of Agriculture, and the other, which appears on product labels, is regulated by the Food and Drug Administration.) A single serving of pasta is 1/2 cup (cooked) according to the USDA, 1 cup according to the FDA and at least 2 cups according to most families.
Eat a variety of fruits and vegetables, but limit your choices of everything else, particularly snacks. Giving folks a wide choice of foods in a single meal, scientists have shown, encourages them to eat more. "It works for every species ever tested--humans, rats, fish, cats," says Susan Roberts, professor of nutrition at Tufts University in Boston. If there are two types of cookies on a plate, the temptation is to eat one of each.
Eventually, you will have to become familiar with the calorie count of your foods. Just a couple of days of measuring or weighing what you eat and calculating the calories you consume can be a real eye-opener. You don't have to do this for the rest of your life, just long enough to get a feel for it. Many nutritionists recommend eating healthy frozen dinners, whose calorie counts are printed on the package, as a good way to make the transition to smaller portion sizes. How many calories you should eat in a day depends on whether you want to lose or maintain weight. The American Heart Association's rule of thumb is to multiply your weight in pounds by 13 (15 if you're active). If you want to lose weight, subtract 250 calories.
ALL FATS ARE NOT CREATED EQUAL
For more than 30 years, most researchers agreed that the healthiest diets were those low in percentage of calories attributable to fat. Now they realize that just as there are good and bad types of cholesterol, there are good and bad types of fat. The good fats--found in foods like fish, olive oil, avocados and walnuts--actually improve cholesterol levels in the blood and significantly reduce the risk that the heart will suddenly stop. As for the bad fats, there are now two villains instead of just one. Saturated fats--typically found in red meat, butter and ice cream--are still champion artery cloggers. But trans fats--found primarily in processed foods, such as margarines and many commercially baked or fried foods but also in whole milk--may be even worse.
Good fats do more than help protect the heart. They also seem to delay hunger pangs. "People on these high-starch, low-fat diets are often hungry soon after they eat. They would be more satisfied eating nuts or a salad with a full-fat dressing," says Dr. Walter Willett, chairman of the department of nutrition at the Harvard School of Public Health and author of Eat, Drink and Be Healthy (Fireside; 2001). "And longer-term studies are showing that people tend to be able to control their weight better over the long run on a moderate or higher-fat diet than on a low-fat diet."