Trans fats are widely considered to be the most dangerous dietary fats. Trans fats raise bad (LDL) cholesterol while lowering good (HDL) cholesterol; this may lead to clogged arteries and increased risk of heart disease and stroke.
Trans fats are created by adding hydrogen to oil, forming a more solid product with a long shelf life and good texture. Trans fats are frequently found in crackers, cookies, bakery products and fried foods.
Food manufacturers are now required to list trans fat on their labels, but even if a food is labeled "trans fat free" it may have small amounts of trans fat. Current nutritional recommendations state that no more than 1% of your total calories should come from trans fats. In addition to looking at trans fat amounts on food labels, look for the words "partially hydrogenated oil" in the ingredient list and avoid it when possible. Some manufacturers are experimenting with trans fat alternatives due to consumer demand for healthier products.
In addition to reading food labels, you can make changes in the way you prepare food to reduce your trans fat intake. Avoid cooking with shortening; it's full of trans fat. Use healthier fats such as olive and canola oils whenever possible. If you use margarine, look for trans-fat-free versions.
Some restaurants are now turning to healthier fats; New York City recently banned the use of trans fat in its restaurants. Even some fast food restaurants, such as Wendy's and Starbucks, have stopped using trans fats in cooking.