Milk, Whole Grain Cereal, OatsSecret Ingredients: Calcium, complex carbohydrates, and fiberHow they work: Complex carbohydrates and fiber pump up metabolism by keeping insulin levels low after you eat. Thats good, because spikes in the production of insulin send a signal to the body that its time to start storing fat. And in order to stockpile fat, your body has to slow down your metabolism, causing you to burn fewer calories, says Margaret McNurlan, Ph.D., a professor of nutrition and medicine at the State University of New York at Stony Brook. Since oatmeal breaks down slowly in the stomach, it causes less of a spike in insulin levels than foods like bagels, she says.Besides helping to keep insulin production down, eating breakfast can also help stoke your daily calorie burn. When the U.S. Navy studied the metabolisms and eating habits of a group of its personnel, it found that eating breakfast helped raise the mens metabolisms by as much as 10 percent. “By skipping meals, you slow down your metabolism and prime your body to store fat,” says McNurlan.The calcium in milk is a metabolic trigger as well. A University of Tennessee study found that dieters who consumed between 1,200 and 1,300 milligrams mg of calcium a day lost nearly twice as much weight as dieters getting less calcium.