What is trans fat?
Trans fatty acids, also known as trans fat, is an artery-clogging fat that is formed when vegetable oils are hardened into margarine or shortening. Trans refers to the chemical makeup of the fatty acid. During a process called "hydrogenation," hydrogen atoms are added to the fat, making it more stable at room temperature. Although small amounts occur naturally in some animal and dairy foods, most of the trans fat in the foods we eat is made from this process.
Trans fatty acids add desirable effects to foods, like making peanut butter creamier and extending the shelf life of packaged products. That's why you are likely to find trans fat in packaged snacks.
What foods contain trans fat?
While bakery items like doughnuts, cookies, pastries, crackers and fried foods like french fries and fried chicken are obvious sources of trans fat, other processed foods, such as cereals and waffles, can also contain the same. One way of determining the amount of trans fat is to read the ingredient label and look for shortening, hydrogenated or partially hydrogenated oil. The higher up on the list these ingredients appear, the more trans fat.
Another way is to add up the amount of fat in a product (saturated, monounsaturated and polyunsaturated), provided the amounts are listed, and compare the total with the total fat on the label. If they don't match up, the difference is likely trans fat, especially if partially hydrogenated oil is listed as one of the first ingredients.
How does trans fat affect our health?
While other heart healthy fats like mono and polyunsaturated types are an important part of a balanced diet, trans fatty acids are not required for normal health. Instead, trans fatty acids are guilty of increasing the risk for coronary heart disease, decreasing "good" cholesterol and increasing "bad" cholesterol, even more so than saturated fats.
When it comes to the amount of trans fat in your diet, it's wise to keep your overall intake to a minimum. If you don't exceed a total fat intake of 5-8 teaspoons a day, you're likely to stay within your fat guidelines.