Trans fat is a type of dietary fat that raises low-density lipoprotein (LDL), or "bad" cholesterol. Saturated fat and dietary cholesterol also raise LDL. Because of this, all three types of fat can boost your risk for heart disease.
Fat, as essential fatty acids, is needed in the body as a source of energy and to help absorb vitamins A, D, E, and K, the FDA says. Fat is important for proper growth and development, as well as to maintain good health. Fat makes food taste good, gives it consistency, and makes you feel full. All this is true when fat is eaten in moderation.
The kind of fat you eat is important. Fat can come from plant or animal sources. Unsaturated fats—monounsaturated and polyunsaturated—come from plant sources and are beneficial when eaten in moderation. Saturated fat and trans fat are not beneficial and should be limited in the diet. You should also limit the amount of dietary cholesterol that you eat.
Trans fat is found in red meat and milk products, but most trans fat comes from processed food products. Trans fats are created when vegetable oil such as soybean or cottonseed has hydrogen atoms added to transform the oil from a liquid into a solid. This process, called hydrogenation, is used most commonly in the manufacture of margarine or shortening. Trans fats provide no known health benefit. Their main function is to give food products a creamy consistency or crispy texture and to increase a product's shelf life.
The biggest problem with trans fats is that they increase the risk for heart disease in two ways. They (1) boost levels of LDL cholesterol while, (2) lowering high-density lipoprotein (HDL) or "good" cholesterol. Overall, a report by the National Academy of Sciences concluded that there is no safe level of either trans fatty acids or saturated fat, and that people should limit their intake of them while consuming a nutritionally adequate diet.
The U.S. Department of Agriculture's 2010 Dietary Guidelines for Americans recommend keeping your consumption of trans fats as low as possible. The American Heart Association’s dietary guidelines recommend that less than 1 percent of your total daily caloric intake come from trans fats. You should also continue to limit saturated fat and dietary cholesterol.
Look for shortening or partially hydrogenated vegetable oil on the ingredient list. Either of these ingredients is a signal that trans fats are present. The closer to the top these ingredients appear, and the more total fat listed, the more trans fat the product contains.
Be aware that products can still make claims such as "low in saturated fat" and "extra lean" and still contain trans fat. The words trans fat free (listed under “saturated fat” on the Nutrition Facts label) mean the product contains less than 0.5 gram of trans fat per serving.
Products in which you're apt to spot partially hydrogenated oil on the Nutrition Facts label and ingredients panel include frozen french fries, ready-made cookies, crackers, doughnuts, frostings, muffins, pastries, and cakes, as well as all deep-fried foods.
But they also can be found in foods where you might not expect them, such as waffles and energy and nutrition bars.
Bake your own cookies, cakes, and breads instead of buying them. Prepare them with olive or canola oil or butter instead of margarine, which contains trans fat.
Trans fat is found in many foods offered at fast-food restaurants, where many of the foods are deep-fried. To reduce your intake, avoid deep-fried foods, such as french fries and fried chicken and fish, and deep-fried Mexican dishes, such as chimichangas and flautas.
Use nonstick frying pans and add a little olive oil instead of lard, butter, or margarine when sautéing. Or, use a nonstick vegetable oil spray, which has few calories. Bake, roast, and steam foods instead of deep-frying or pan-frying.
You can improve your health by lowering your intake of trans fat and saturated fat; replace them with polyunsaturated and monounsaturated fats. Polyunsaturated fats are found in vegetable and fish oil, and monounsaturated fats are in olive, canola, and peanut oils.
If you use margarine, choose brands that contain no trans fat.
Remember that not all trans fat comes from hydrogenated vegetable oil. It also is found in meat. To lower your intake, eat three or fewer servings of lean red meat per week.
Here are some examples of trans fat and saturated fat found in common foods.
Saturated fat: 3 grams
Trans fat: 0 grams
Saturated fat: 7 grams
Trans fat: 0 grams
Saturated fat: 2 grams
Trans fat: 3 grams
Saturated fat: 1 gram
Trans fat: 0.5 gram
Saturated fat: 5 grams
Saturated fat: 5 grams