The U.S. Food and Drug Administration (FDA) requires food manufacturers to display the amount of trans fats on all of their product labels. You'll see this number listed on the Nutritional Facts panel after Total Fat and Saturated Fat. Dietary supplements (such as energy and nutritional bars) will also list trans fats on their Supplement Facts panel if the product contains 0.5 grams or more of trans fat.
Trans fats are created when manufacturers turn liquid oils into solid fats through a process called hydrogenation, which was originally done to increase the shelf life of foods. But we now know that consuming trans fats contributes to clogged arteries -- which can lead to heart disease or stroke.
Besides listing the amounts of trans fats, these labels will also tell you the amounts of saturated fats and cholesterol so you can compare products and choose the ones with the lowest amounts. Why should you be concerned about these numbers? Consuming trans fats raises your LDL ("bad") cholesterol levels, which in turn increases your risk for heart disease, stroke, obesity, and other conditions. These fats also lower your HDL, the good, protective form of lipids. Foods high in saturated fats and cholesterol can also increase your risk for heart disease, but since trans fats have a negative effect on both HDL and LDL, they probably pose an even greater risk than saturated fats.
Try to minimize your intake of trans fats as much as possible, and instead focus on eating products containing the "good" fats, such as extra-virgin olive and canola oils.
Learn more in the Everyday Health Heart Health Center.