There are natural and artificial versions.
They form naturally in some meat and dairy products in very small amounts. The Trans Fats we hear about in the media are industrially manufactured when hydrogen is added to vegetable oil to make it more solid. These oils are inexpensive and used to improve the texture, shelf life, and flavor of foods.
They are bad for the heart.
Trans fats raise the bad (LDL) cholesterol and lower the good (HDL). This increases the risk for heart disease which is the #1 killer in the United States.
They are in some of your favorite foods.
French fries, doughnuts, baked goods, frozen pizza, pies, cookies, crackers, microwave popcorn, and cakes contain artificial trans fats.
They add up fast.
The American Heart Association recommends limiting the amount of trans fats you eat to less than 1% of your total daily calories. So if you need 2000 calories a day that is less than 2 grams of trans fats, natural and artificial. Microwave popcorn alone can contain as much a 7 grams.
They are not always obvious.
Sometimes trans fats hide in the ingredient list. Manufacturers are required to list any amount greater than 0.5 grams per serving on the nutrition label which means even if the label says “0 grams trans fats” the food could still contain some. If the label says “partially hydrogenated oil,” the products contains trans fats. Instead, look for healthier monounsaturated and polyunsaturated fats like olive and canola oil.