You may not even know you are eating them, but trans fats will eventually be a thing of the past. The U.S. Food and Drug Administration says it is phasing them out, calling them a threat to public health. Some questions and answers about the dangerous fats:
Q: What are trans fats?
A: Trans fats, also called partially hydrogenated oils, are created when hydrogen is added to vegetable oil to make it more solid. They can contribute to heart disease and are considered even less healthy than saturated fats, which can also contribute to heart problems.
Q: How do I know if I am eating them?
A: You won't be able to taste them, but they do help give a more solid texture and richness to certain foods, like baked goods and ready-to-eat frostings. Some restaurants use them to fry food and they are also sometimes used in microwave popcorn, biscuits and pie crusts. You'll know you are eating them by looking on the nutrition label of a packaged food - the FDA has required labeling of trans fats since 2006.
Q: Why are they so bad for you?
A: Trans fats can raise ''bad'' cholesterol and lower ''good'' cholesterol. That can contribute to heart disease - the leading cause of death in the United States.
Q: Are all fats bad for you?
A: No, but they should be eaten in moderation. Unsaturated fats found in nuts, vegetable oils and fish are the best for you. Saturated fats mostly derived from animals are less healthy and should be less than 10 percent of a person's daily calories. Total fat should make up no more than 35 percent of calories a day, according to the federal Centers for Disease Control and Prevention.
Q: How long have these trans fats been around?
A: For over 100 years, according to the American Heart Association. They were first found on grocery shelves in 1911, with the introduction of Crisco vegetable shortening. Its use became more widespread during World War II when butter products were rationed and people started using margarines that contained trans fats. Many margarines are now trans fat free, as is Crisco.
Q: How will the trans fats be phased out?
A: The FDA announced Thursday that it has made a preliminary decision that trans fats no longer fall in the agency's ''generally recognized as safe'' category, which is reserved for thousands