The FDA made the announcement Thursday, saying the new requirement on the food industry could prevent 20,000 heart attacks and 7,000 deaths each year, according to Commissioner Margaret Hamburg.
Hamburg said trans fats "remain an area of significant public health concern" although the amount of trans fats in the country's diet has declined dramatically in the last decade. Trans fats have long been criticized by nutritionists, and New York City and other local governments have banned them.
The FDA has not set a timeline for the phase-out, but the agency said it will collect comments for 60 days before officials decide how long it will take. Different foods may have different timelines, depending how easy it is to find a substitute.
Michael Taylor, FDA's deputy commissioner for foods, said the phase-out plan will aim to not unduly disrupt markets. Still, he says, the food "industry has demonstrated that it is, by and large, feasible to do."
Though trans fats have already been removed from many items, they are still found in processed foods, including in some microwave popcorns and frozen pizzas, refrigerated doughs, cookies, biscuits and ready-to-use frostings. Restaurants also sometimes use them for frying. Many larger chains have phased them out, but smaller restaurants may still get food containing trans fats from suppliers.
Trans fats are widely considered the worst kind for your heart, even worse than saturated fats, which also can contribute to heart disease. Trans fats are used in processed food and in restaurants, often to improve the texture, shelf life or flavor of foods. Diners shouldn't be able to detect a taste difference if trans fats are replaced by other fats.
"If you look at what trans fats do, they're bad actors. They are going to raise your LDL, or bad cholesterol. They lower your HDL, or good cholesterol," said Dr. Richard Besser, ABC News' senior medical editor.
In order to phase trans fats out, the FDA has determined they no longer fall into the agency's "generally recognized as safe" category, which is reserved for thousands of additives that manufacturers can add to foods without FDA review. Once trans fats are off the list, anyone who wants to use them would have to petition the agency for a regulation allowing it, and that would likely not be approved.
The FDA is not targeting small amounts of trans fats that occur naturally in some meat and dairy products, because they would be too difficult to remove and aren't considered a major public health threat on their own.
Scientists say there are no health benefits to trans fats and say they can raise levels of so-called "bad" cholesterol, increasing the risk of heart disease - the leading cause of death in the United States.
According to FDA officials, the agency has been working on trans fat issues for around 15 years. Its first goal was to label them. The agency says since trans fat content information began appearing in the nutrition facts label of foods in 2006, trans fat intake in American consumers has declined from 4.6 grams per day in 2003 to about 1 gram per day in 2012.
The Associated Press contributed to this report.
