Dietary fats

Fats, carbohydrates and proteins are the three main components of food. Fats are a concentrated source of energy in the body.


General information
Fats are an essential element in your diet. They provide a vital source of energy and allow your body to absorb vitamins A, D, E and K. Your body uses fats to make steroids and hormones.
Because unused fat is stored as tissue beneath the skin, fat insulates your body and helps maintain body temperature. Body fat also cushions and protects vital organs, including the kidneys, heart and liver.

Fats help satisfy your appetite and delay hunger because they're digested slowly. In addition, they contribute to the flavor, texture and palatability of food.

Too much dietary fat, however, increases the risk of obesity, heart disease and possibly certain cancers.


Types of fat
There are several types of dietary fat. The percentage of each type of fat in certain foods makes some foods healthier choices than others. Here are some common examples:
Saturated fats
Foods from animal products such as meat or dairy products, as well as coconut, palm and palm kernel oils, are especially high in saturated fat. The main sources of saturated fat in the typical American diet are meats, full-fat dairy products, high-fat snacks and bakery products. Saturated fats are usually solid at room temperature, like butter and shortening. Of the three types of dietary fats, saturated fat plays the largest role in increasing the risk of high cholesterol and heart disease.

Polyunsaturated and monounsaturated fats
Polyunsaturated fats reduce blood cholesterol levels when they replace saturated fat in the diet. This type of fat, which typically comes from a vegetable, seed or nut, is liquid at room temperature. Some research indicates that omega-3 fatty acids, a type of polyunsaturated fat, may lower low-density lipoprotein (LDL or "bad") cholesterol and triglyceride levels. Triglycerides are essentially your body's stored fat reserves.

To increase your intake of omega-3 fatty acids, you may want to eat more fatty fish, such as salmon, sardines, herring and mackerel. If you're considering taking dietary supplements containing concentrated levels of fish oil, consult your doctor about the potential risks and benefits.

When used in place of saturated fats, monounsaturated fats can reduce LDL cholesterol levels (the "bad" kind). This type of fat, which is found in olive, peanut and canola oils, is also liquid at room temperature.

Both polyunsaturated and monounsaturated fats can become saturated through a process called hydrogenation, which makes the fat more solid at room temperature. Hydrogenation is used to produce vegetable shortening and help processed foods last longer.

Trans fats
Watch out for the terms "hydrogenated" or "partially hydrogenated" on food labels -- they indicate trans fats, which are prominent in foods such as margarine and shortening, as well as products such as cookies, crackers, cake, doughnuts and french fries. Trans fats can raise your total and LDL cholesterol (the "bad" kind), as well as lower your HDL cholesterol (the "good" kind).

Cholesterol
Cholesterol is a waxy, fat-like substance found in foods that come from animal sources, such as dairy products and meat (especially red and organ meats). Cholesterol isn't found in plant-derived foods.

Cholesterol helps the body absorb fatty acids, make vitamin D, and produce both male and female hormones. You can't live without it. However, as an adult, your body manufactures all the cholesterol it needs to stay healthy. Any cholesterol you consume from food is extra.

Because excess cholesterol can block the blood vessels in your heart, most experts recommend limiting your cholesterol intake to no more than 300 milligrams per day and to limit saturated fat intake. Many foods high in saturated fat are also high in cholesterol.


Food labels
Food labels list total fat and the percentage of daily values for various nutrients, making it easier to keep track of your daily nutritional intake. As food manufacturers compete in a market of health-conscious consumers, however, labels can become confusing. Here are the legal definitions for some common terms:
Fat free: Contains less than 0.5 grams of total fat per serving.
Low fat: Contains no more than 3 grams of total fat per serving.
Low in saturated fat: Contains no more than 1 gram of saturated fat per serving and 15 percent or less of calories are from saturated fat.
Cholesterol free: Contains less than 2 milligrams of cholesterol and 2 grams of saturated fat per serving.
Low in cholesterol: Contains no more than 20 milligrams of cholesterol and 2 grams of saturated fat per serving.
Reduced fat, less fat, lower in fat, lower fat: Contains at least 25 percent less total fat than the regular product.
Light: Contains at least one-third fewer calories or 50 percent less fat than the regular product.
Extra lean: Contains less than 5 grams of total fat, 2 grams of saturated fat, and 95 milligrams of cholesterol per 100-gram serving of meat or poultry (about 3 ounces).
Lean: Contains less than 10 grams of total fat, 4.5 grams of saturated fat, and 95 milligrams of cholesterol per 100-gram serving of meat or poultry (about 3 ounces).
Beginning January 2006, manufacturers will be required by the U.S. Food and Drug Administration (FDA) to list trans fat content on food labels.


Daily fat intake
The National Cholesterol Education Program and the American Heart Association recommend limiting your total daily fat intake to 30 percent or less of your daily caloric intake. Saturated fats should account for less than 10 percent of this total, and monounsaturated and polyunsaturated fats should make up the remainder. The National Academies' Institute of Medicine recommends adults get 20 to 35 percent of their daily calories from fat.
To translate the total percentage to actual fat grams, multiply your total calories for the day by the percentage and divide the total by nine. For specific advice about caloric and fat intake, consult your doctor or a registered dietitian.


Low-fat diets
A balanced, low-fat diet can help you control your weight and prevent or reduce the risk of heart disease and other chronic conditions. Low-fat diets are often recommended for people who have certain medical conditions, including high cholesterol, heart or gallbladder disease, malabsorption syndromes or other conditions in which the body can't tolerate dietary fat.
To limit your fat intake:

Try low-fat recipes. Opt for lean meats, fish, skinless poultry, beans, fruits, vegetables, rice, pasta, and low-fat or fat-free dairy products. Eat more fiber and fewer animal products and saturated fats.

Use fats such as butter and oils sparingly. When you use oil, opt for olive or canola oils. Avoid products with coconut, palm or palm kernel oils. Avoid cream, cheese or butter sauces.

Use reduced or no-fat salad dressings for salads, dips or marinades.

Trim all visible fat from meats, and remove the skin from poultry.

Broil, poach, grill, stir-fry or roast meats. Drain the fat from the pan before serving.

Substitute broth for grease or fats when cooking main and side dishes.

Season with herbs, spices or lemon juice.

Choose spreads made with vegetable oil that have no more than 2 grams of saturated fat per tablespoon. Look for brands that list liquid vegetable oil as the first ingredient. Choose soft margarine, which is lower in trans fats, over the stick variety or butter.

When baking, substitute chocolate with powdered cocoa.

Pregnancy-specific information
A healthful, well-balanced diet is essential during pregnancy. Again, fat is an important source of energy. Dieting and weight loss are not recommended during pregnancy.

Senior-specific information
The risk of developing heart disease and diabetes increases with age. Limiting the amount of fat in your diet may help prevent various chronic diseases. Consult your doctor or a registered dietitian about your specific dietary needs.