Dreamstime_s_4678292If you're up on your nutrition news, you've probably heard by now that trans fats are bad for you. By raising levels of "bad" LDL cholesterol and lowering levels of "good" HDL cholesterol, trans fats can contribute to your risk of heart attacks, heart disease, and strokes. They're also associated with a higher risk of developing type 2 diabetes. With all these dangers, it's no surprise that the FDA required trans fat to be listed on the Nutrition Facts label, beginning in 2006. As a result, Americans are snapping up products that proudly advertise themselves as having "0 grams trans fat." But even if you're reading the label and only purchasing products with 0 grams of trans fat, you might still be consuming it. How is that possible? We've got the answers.

What Is Trans Fat?

Trans fats, also known as trans fatty acids, are created by adding hydrogen to liquid vegetable oils in order to make them more solid. It increases the shelf life of foods and improves their flavor, making it a common addition to packaged snack foods like pastries, pie crust, pizza dough, cookies, and crackers. It's also in stick margarine and shortening, and can appear in oils used for frying foods. Small amounts of naturally produced trans fat are present in beef, lamb, and butterfat, but their effect on health is still unknown. Before 1990, little was known about industrially-produced trans fats, and they were generally considered safe. Over the course of the 1990s, however, more and more medical research pointed to the dangers of trans fats. 

How Much Trans Fat Can I Have?

Both the Dietary Guidelines for Americans, 2010 and the American Heart Association say you should keep your intake of trans fats as low as possible. They recommend you limit foods that contain synthetic trans fats like those found in some packaged foods, frying oils, baked goods, etc. and limit your intake of solid fat by regularly choosing lower-fat milk and lean meats over higher-fat options. The American Heart Association recommends that Americans consume no more than one percent of their calories as trans fats. For someone on a 2,000 calorie diet, this would mean no more than 20 calories, or roughly 2 grams of trans fat, per day. Because of the small amount of naturally occuring trans fat in whole foods, this recommendation means that Americans have no room in a healthy diet for the trans fats found in some packaged and processed foods.

When Doesn't Zero Mean Zero?

So you checked the Nutrition Facts, and the food you're purchasing has 0 grams trans fat. But don't throw it into your cart just yet. When it comes to FDA labeling, 0 grams actually means less than 0.5 grams– per serving. While an eighth of a box of cookies might have only 0.4 grams of trans fat (which equals 0 in FDA math), eating the whole thing, even over the course of a week or two, can add up to 3.2 grams of the stuff– enough to have a potentially negative effect on your health. Multiply that by multiple products, consumed multiple times, and the risks are clear.

The best way you can avoid hidden trans fat is to read the list of ingredients in a product. On ingredient labels, trans fat will usually be listed as "partially hydrogenated ______ oil," with soybean, vegetable, and coconut as some of the potential oils filling the blank. And when you're at restaurants, be wary of signs proclaiming newly healthy habits: do they say "0 grams trans fat," or "No trans fat"? There's a difference between the two. Ask for their nutrition and ingredient information to make sure.

Figuring out which foods contain trans fats isn't always easy, but ShopWell is on your side. We screen both the nutrients section and in the ingredients list for potential trans fats, finding any hidden trans fats in foods with Nutrition Facts proclaiming they have 0 grams of the stuff. Sign up, and get the real skinny on your favorite foods.