You don't have to be. While eating too much fat (or carbohydrates or protein for that matter) isn't healthy, we need some fat in our diets for good health - and to make food taste great.
Dietary fat plays several important roles in good health:
- Helps the body absorb
fat-soluble vitamins A, D, E and K, and
carotenoids such as
- Provides the essential fatty acids
linoleic acid and alpha-linolenic acid, needed
for healthy skin, normal brain and nervous
system functioning and normal growth in
- Regulates cholesterol metabolism and is
necessary for the body to produce
prostaglandins, hormone-like substances that
regulate many body
- Offers an important energy source. Fat
provides nine calories per gram. Carbohydrates
and protein each provide four calories per
- Promotes feelings of satisfaction and
fullness after eating because it's digested
- Gives foods "palate appeal" by enhancing flavor, aroma and texture.
Food actually contains several types of fat. Fats, which are "built" from carbon, hydrogen and oxygen, are combinations of different fatty acids, generally classified as saturated or unsaturated. Monounsaturated and polyunsaturated fats are types of unsaturated fats.
Certain fats are often referred to as being "saturated" or "unsaturated," but they're really a combination of both types of fatty acids. Generally, fats containing mostly saturated fatty acids are solid at room temperature (e.g., butter) and those containing mostly unsaturated fatty acids are liquid at room temperature (e.g., oil).
Monounsaturated fat reduces risk for heart disease by lowering total cholesterol and the level of low-density lipoprotein (LDL), often referred to as "bad" cholesterol, and raising the level of high-density lipoprotein (HDL), often referred to as "good" cholesterol, in the blood. Monounsaturated fat is found in olive oil, canola oil, almonds, peanuts and avocados.
Polyunsaturated fat reduces risk for heart disease by lowering total cholesterol and LDL cholesterol levels in the blood. However, polyunsaturated fats also may lower HDL cholesterol. Polyunsaturated fat is found in corn, safflower, soybean and sunflower oils, sunflower seeds and walnuts.
Saturated fat increases risk for heart disease by raising total cholesterol and LDL cholesterol levels in the blood. Saturated fat is found in foods from animals such as meat, poultry, whole milk, cheese, ice cream, and in coconut, palm and palm kernel oils.
Trans fatty acids or trans fats increase risk for heart disease by raising total cholesterol and LDL cholesterol. Trans fats are formed during a process called "hydrogenation" that makes liquid oils into solid fats such as shortening and hard margarine. Hydrogenation increases the shelf life and flavor stability of foods containing these fats. Trans fat is found in processed foods made with partially hydrogenated vegetable oils such as vegetable shortenings, some margarines (especially harder margarines), crackers, candies, cookies, snack foods, fried foods, and baked goods. A small amount of trans fat is found naturally in foods from animals such as beef, pork, lamb, butter and milk. The Food and Drug Administration requires that the number of grams of trans fat in a serving of food appear on the Nutrition Facts label by January 1, 2006. This information already appears on many labels.
Omega-3 fatty acids are a type of polyunsaturated fat that may reduce risk for heart disease by reducing blood triglyceride levels, making the blood less likely to form clots, protecting against irregular heartbeats and slightly lowering blood pressure. Alpha-linolenic acid, one of the essential fatty acids, is a type of omega-3 fatty acid. Omega-3s are found in fatty fish such as salmon, mackerel, lake trout, herring, sardines and albacore tuna.
Omega-6 fatty acids are a type of polyunsaturated fat that may reduce risk for heart disease by lowering total cholesterol and LDL cholesterol. However, they also may lower HDL cholesterol. Linoleic acid, one of the essential fatty acids, is a type of omega-6 fatty acid. Omega-6s are found in vegetable oils such as soybean, corn and safflower oil.
Conjugated linoleic acid (CLA) is a form of linoleic acid. Preliminary animal research suggests that CLA may suppress cancer cell development, help reduce risk of heart disease, boost the immune system, build lean muscles, and reduce body fat. CLA is found in lamb, beef, turkey, milk, cheese and butter.
For good health, the Dietary Guidelines for Americans recommend that healthy adults and children age two and older aim for a total fat intake of no more than 30 percent of calories and a saturated fat intake of less than 10 percent of calories per day. These percentages refer to the overall eating pattern, not individual foods. In addition, the Institute of Medicine recommends that we reduce trans fats in the diet as much as possible. On average, Americans eat 33 percent of calories from total fat, 12 percent of calories from saturated fat and 2-3 percent of calories from trans fat in the diet. The box below shows upper limits on saturated and total fat for several daily calories levels.
|Use the Nutrition Facts label to determine the amount of total fat, saturated fat and, if available, trans fat in a serving of food. This information helps you compare similar products to choose the one that best fits your eating plan.|
|Select lean cuts of meat. Meat with the words "round" and "loin" in the name (e.g., ground round or top sirloin) tend to be leaner.|
|Buy skinless turkey and chicken, or remove the skin before eating.|
|Bake, broil, grill or roast foods instead of frying.|
|Use an unsaturated oil such as olive, canola, corn, safflower or soybean oil.|
|Eat sensible portions. A good guideline for poultry and meat is to choose a portion of 3 to 4 oz. That's about the size of a deck of cards.|
|Choose reduced fat, low fat or fat free versions of dairy products such as milk, cheese and yogurt.|
|Use reduced fat versions of salad dressing, mayonnaise and sour cream.|
|Use a spread labeled "trans fat free."|
- Background on Dietary Fats & Fat
Replacers. Available at: http://www.ific.org/nutrition/fats/index.cfm.
Accessed May 23, 2004.
- Conjugated Linoleic Acid and Dietary
Beef - An Update. Available at: http://www.beef.org/documents/23348_Conjugated.pdf.pdf
Accessed May 23, 2004.
- Duyff RL. The American Dietetic
Association's Complete Food & Nutrition
Guide. 2nd ed. New York: John Wiley; 2002, in
- IFIC Review: Sorting Out the Facts About
Fat. Available at: http://www.ific.org/publications/reviews/fatir.cfm.
Accessed May 23, 2004.
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) Washington, D.C., National Academy Press, 2002.