Count calories, says Alice H. Lichtenstein, a professor at the Friedman School of Nutrition Science and Policy at Tufts University, in Boston: "Total calories―not the amount of sugar, carbs, or fat―is the big issue associated with controlling weight gain."
Pay attention to serving size, advises Connie Weaver, Ph.D., head of the department of food and nutrition at Purdue University, in West Lafayette, Indiana. "Most commercial muffins weigh about 120 grams. A standard muffin serving size is 40 grams. The muffins we buy are equivalent to about three servings."
Look for foods with "whole grain" near the top of the ingredients list, says Walter C. Willett, M.D., chairman of the nutrition department at the Harvard School of Public Health. "Then check for possible trans fats, like partially hydrogenated vegetable shortening," he says.
Beware of hidden sodium, cautions Carol Boushey, Ph.D., R.D., associate professor of foods and nutrition at Purdue University. "Sodium content is something I always consider carefully," she says, "especially when purchasing condiments." Foods like ketchup and relish often have surprisingly high sodium levels (100 milligrams or more) in just a teaspoon or a tablespoon.