At least 30,000 fewer Americans would die each year from coronary heart disease if trans fatty acids—also known as trans fat—in foods were replaced with unsaturated vegetable oil, according to a study by scientists at the Harvard School of Public Health and in the Netherlands.

What Is Trans Fat?

Trans fat is created during a process called hydrogenation—where vegetable oils are turned into a more solid shortening by adding hydrogen molecules. Hydrogenation is popular with food manufacturers because it increases shelf life and flavor stability of the oils and foods made with them. Trans fat is also commonly used in fast food restaurants because it stands up well to heat in deep frying and can be used for longer periods of time. While trans fat may make economic sense for food manufacturers, it raises a numbers of serious health concerns for the consumer. For a start, it elevates blood cholesterol levels in the same way as saturated fat. Trans fat also raises levels of LDL, the "bad" cholesterol. Regular consumption of foods high in trans fat may also interfere with the body's ability to metabolize fats that are important for the growth and functioning of vital organs such as the brain.

What Foods Are Trans Fat In?

According to a study by the American Dietetic Association, one of FoodFit's Resource Associations, Americans consume most of their trans fat in partially hydrogenated vegetable oils, like margarine. Trans fat is found in vegetable shortenings, some margarine, crackers, cookies, snack foods and other foods. Since it's frequently used in fast food places, children often gobble it up in French fries, even when a restaurant says it's using 100 percent vegetable oil. Currently, the Food and Drug Administration requires food companies to label grams of unsaturated fats and saturated fat, but not trans fats. So while consumers may do their best to choose foods that are supposedly heart healthy and low in cholesterol and saturated fats, they may well actually be eating foods high in unhealthy trans fat. This will be changing when the Nutrition Facts label begins including trans fat in 2006.

To avoid trans fat: If the ingredient list on a food includes hydrogenated or partially hydrogenated oils, you should limit your consumption of the product. Avoid deep-fried foods, particularly at fast food restaurants. If you're using margarine, be sure to pick one that claims to have no trans or hydrogenated fats. Foods that may be laden with trans fat: candy cookies crackers doughnuts potato chips non-dairy creamers deep fried burgers deep fried fish fried chicken salad dressings processed peanut butter some cereals margarine

— Ruth Prince