Although it might seem that the cholesterol in your diet would have the greatest impact on your blood levels of cholesterol, that's not true, the American Heart Association (AHA) says. Saturated fat is the main culprit. Saturated fat is found in foods from animals and in some plant foods. Animal sources include beef, veal, lamb, pork, poultry and whole milk dairy products. (Cholesterol is also found in these foods.) Plant foods that contain saturated fat include coconut, palm and palm kernel oils and cocoa butter. High cholesterol levels are a risk factor for heart disease.

Your total fat calories should be no more than 30% of all the calories you eat each day. If you have heart disease or a high level of LDL ("bad") cholesterol, you may need to restrict your saturated fat to 5% to 6%, the AHA says. Limiting fat shouldn't be the sole focus of a healthy diet, however. Total calories are also important. To not gain weight, you must balance the number of calories you consume with the number of calories you expend in exercise and other daily activity.

Other examples of monounsaturated fats are olive and peanut oils. Avocados also contain monounsaturated fats. Safflower, soybean, and walnut oils are polyunsaturated fats. Both of these types of fat come from plants, and both may help lower your cholesterol levels. Each gram of fat contains 9 calories, compared with 4 calories for each gram of carbohydrate or protein. Any fat should be used in moderation to keep your weight under control.

Meat products and whole milk dairy products contain small amounts of trans fat. Commercial bakery and snack products typically contain higher amounts of trans fat. The trans fat comes from the hydrogenated oil used in making these products. Hydrogenated oil is used because it has a longer shelf life than other fats. The FDA requires that food labels state the amount of trans fat in a product. The AHA recommends limiting trans fats to 1% of total calories. Some brands of soft margarine such as tub margarine have little or no trans fat. Other food makers are making an effort to decrease or drop trans fat from their products.

Keep in mind that fat has 9 calories per gram. To do the math, multiply 2,000 by 0.30. That equals 600 calories of fat. That figure divided by 9 equals about 67 grams. If you consume 2,500 calories a day, your total fat should be no more than 83 grams. If you consume 1,800 calories a day, your total fat should be no more than 60 grams.

According to the AHA, fat substitutes are based on one of these 3categories: carbohydrates, protein, and fat. Carbohydrate- and protein-based substitutes replace the fat in a product. Carbohydrate-based substitutes include okra gum, pureed cannellini beans, and mung bean paste. Protein-based substitutes include egg-white proteins, dairy proteins, and whey protein concentrate. Fat-based substitutes such as olestra are not absorbed efficiently from the intestines. According to the FDA, all 3 types are considered safe.