BOSTON, MASS – Although small amounts of trans fat are naturally found in dairy and meat products, the origin of the trans fat problem goes back to the development of margarine as a cheap alternative to butter. In the early 1900s, food chemists discovered that, through a process called hydrogenation, they could convert healthy vegetable oil into a new type of fat that could remain solid at room temperature and stay on the shelf longer. This new type of fat — trans fat — is the unhealthiest of all fats.

Trans fats are a double whammy to your arteries, according to the March 2004 issue of Harvard Women's Health Watch . Trans fat raises LDL cholesterol and lowers HDL cholesterol — the worst possible combination. Harvard School of Public Health researchers estimate that trans fat consumption is responsible for at least 30,000 premature heart disease deaths annually in the United States .

Harvard Women's Health Watch recommends these strategies for lowering your trans fat intake:

Be label savvy. If a product lists shortening or hydrogenated or partially hydrogenated oil as one of its first ingredients, beware — it has a lot of trans fat! Do some math. Soon, food labels will be required to list trans fat content. For now, you can figure it out yourself. Add the polyunsaturated and monounsaturated fats to the saturated fat. Subtract the sum from the “Total Fat” listed on the label — what's left is trans fat. Choose the better spreader. The softer a margarine is at room temperature, the lower the trans fat content. Margarines labeled “trans fat–free” are best. Fry wisely. Use canola oil or olive oil. Watch out when you go to restaurants — foods that are fried in partially hydrogenated vegetable oil are labeled “cholesterol free” or “cooked in vegetable oil.” Make it yourself. Commercial breads, soups, cereals, dips, salad dressings, and packaged entrees usually have hidden trans fats.