WASHINGTON (AP) — The FDA is announcing Thursday that it will require the food industry to gradually phase out trans fats, saying they are a threat to people's health. Commissioner Margaret Hamburg says the move could prevent 20,000 heart attacks a year and 7,000 deaths. Hamburg says that while the amount of trans fats in the country's diet has declined dramatically in the last decade, they "remain an area of significant public health concern." The agency isn't yet setting a timeline for the phase-out, but will collect comments for two months before officials determine how long it will take. Trans fat is widely considered the worst kind of fat for your heart. They are often found in processed foods, including some microwave popcorns and frozen pizzas, refrigerated doughs and ready-to-use frostings.