Please note: This information was current at the time of publication but now may be out of date. This handout provides a general overview and may not apply to everyone. 

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Am Fam Physician. 2009;80(4):372

See related article on trans fats.

What are trans fats?

Trans fats are a type of fatty acid. Fatty acids are a source of energy for your body. Fatty acids come from fruit and vegetable oils, seeds, nuts, animal fats, and fish oils. Not all fatty acids are unhealthy, but some, such as trans fats, can be bad for you. Trans fats are often used in processed foods and baked goods because they are cheaper than animal fats, have a wide range of textures, and have a longer shelf life.

What types of foods contain trans fats?

Margarines, shortening, crackers, cookies, chips, salad dressings, and fried foods may be made with trans fats. Many foods from fast food restaurants also have high levels of trans fats.

Why are they unhealthy?

Trans fats may increase the levels of bad cholesterol in your body and decrease the levels of good cholesterol. Studies have found that eating more trans fats is linked to a higher risk of heart disease.

How do I avoid them?

You should add more fruits and vegetables to your diet in place of some packaged foods. Fruits and vegetables are naturally free of trans fats. You should also read food labels carefully. Many foods now say “ trans fat free” on the package.

Food labels must list trans fats, total fat, saturated fat, and cholesterol. Trans fats may also be listed on food labels as hydrogenated (hi-DRAW-je-nate-ed) or partially hydrogenated vegetable oils. Some fast food restaurants do not use trans fats anymore, but it is important to ask before you order. The American Heart Association recommends that no more than 1 percent of your total calories per day come from trans fats. This equals about 2 to 2.5 grams per day.

Where can I get more information?

Your doctor

American Academy of Family Physicians

American Heart Association

Fast Food Facts

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