Trans Fats

There are two types of trans fat: the kind that occurs naturally in small amounts in animal products, and the artificial kind produced by adding hydrogen to liquid oils so they remain solid at room temperature, which helps extend a food's shelf life. So far no studies have examined how natural trans fat impacts health, but the artificial kind raises levels of LDL ("bad") cholesterol and lowers HDL ("good") cholesterol, raising the risk of heart disease.

• Where it's found: Most commercially produced fried foods, baked goods, and stick margarines are made with artificial trans fat. Natural trans fat can be found in red meat, milk, butter, and cheese.

• How much to eat: As little as possible. The American Heart Association (AHA) suggests limiting trans fat to less than one percent of your daily calories, about two grams if you follow a 2,000-calorie-per-day plan. That figure includes artificial trans fat as well as natural, since natural trans fat sources are often high in another type of fat linked to heart-disease risk factors-saturated fat.
• Recent news: New York Los Angeles, California; Philadelphia, Pennsylvania; and Boston -- have legislation pending or have approved legislation to limit or ban artificial trans fat.