Fats help your body absorb many essential vitamins, maintain the structure and function of cell membranes, and preserve the integrity of your immune system. But fat is a very concentrated energy source, providing twice as many calories per gram as carbohydrates and protein. And too much of certain types of fat — such as saturated fat and trans fat — can increase your blood cholesterol levels and your risk of coronary artery disease.
Limit fat to 20 percent to 35 percent of your daily calories — 40 to 70 grams of fat a day if you consume a 2000-calorie diet. Emphasize fats from healthier sources, such as nuts and olive, canola and nut oils.