US regulators took steps to eliminate artery-clogging trans fats from processed foods like margarine, microwave popcorn and frozen pizza, saying that partially hydrogenated oils are not safe to eat.

The proposal by the Food and Drug Administration aims to reduce heart disease and deaths by requiring packaged food-makers to choose safer mono and polyunsaturated fats.

The ban would not take effect right away. First, there is a 60-day comment period before the rule can become final. The FDA is also seeking feedback from industry on how long it would take them to change their recipes.

If the decision is made final, partially hydrogenated oils, which are made by incorporating hydrogen into liquid oil to make solid fat, would be considered food additives and could not be used in food unless given special regulatory approval.

Trans fats carry no health benefits, and the Institute of Medicine has determined that no level is safe for consumption.

The FDA said that “since trans fat content information began appearing in the Nutrition Facts label of foods in 2006, trans fat intake among American consumers has declined from 4.6 grams per day in 2003 to about 1 gram per day in 2012.”

FDA Commissioner Margaret Hamburg said despite declines in consumption of trans fats over the past decade, Americans’ “current intake remains a significant public health concern.”

Cutting out trans fats in the American diet “could prevent an additional 20,000 heart attacks and 7,000 deaths from heart disease each year,” she said.

The FDA said its decision would not affect trans fats that occur naturally in some meat and dairy products, but would apply to man-made partially hydrogenated oils that are added to processed foods.

These fats, also known as PHOs, are commonly added to improve flavor and lengthen the shelf life of products like cookies, pies, cake frosting, chips, crackers, doughnuts, pizzas, margarine, coffee creamer and some cereals.

Eating trans fats causes an increase in bad cholesterol, or low-density lipo-protein (LDL), a leading risk factor in the development of coronary heart disease, which is the top cause of death in the United States, according to the Centers for Disease Control and Prevention.

Many food manufacturers have voluntarily cut back their use of trans fats after a public health campaign to warn of the dangers built steam.

“But a substantial number of products still contain partially hydrogenated oils, which are the major source of trans fat in processed food,” said Michael Taylor, the FDA’s deputy commissioner for foods and veterinary medicine.

"It may take some time" for food-makers to find ways to comply, he added.

Industry would have a high standard to meet in order to be able to use trans fats as a food additive.

It must be "demonstrated scientifically that there is a reasonable certainty of no harm from use of the ingredient," he told reporters.

"Companies are free to petition but they would have to meet that rigorous safety standard."

The FDA move was hailed by consumer groups as a major step forward.

"Artificial trans fat is a uniquely powerful promoter of heart disease, and today's announcement will hasten its eventual disappearance from the food supply," said Center for Science in the Public Interest executive director Michael Jacobson.

"Not only is artificial trans fat not safe, it's not remotely necessary. Many companies, large and small, have switched to healthier oils over the past decade."

Food industry representatives said they would cooperate with the FDA.

"Consumers can be confident that their food is safe and we look forward to working with FDA to better understand their concerns and how our industry can better serve consumers," the Grocery Manufacturers Association said in a statement.

Nutrition experts and doctors applauded the FDA move, but warned that consumers should still be careful about saturated fat and cholesterol.

"If and when food manufacturers reformulate their products to remove trans fats, they often replace the hydrogenated oils with things like coconut and palm oil that are high in saturated fat,” said Dana Angelo White, assistant clinical professor at Quinnipiac University.