We've made great progress since January 2006, when Congress required that trans fat content be listed on food labels. Food manufacturers and restaurants that used the unhealthy fats have scrambled to find alternatives so they can boast of their "trans-fat-free" foods. Bills to limit or ban trans fats in restaurants or school cafeterias have been introduced in many states.
Artery-clogging trans fats have been made out to be the bad guy in American diets -- and there's good reason for that. But the truth is that just because something is trans-fat-free, that doesn't necessarily mean it's healthy. Experts agree that using healthy fats, such as canola oil, olive oil, and plant sterols is better than using the artery-clogging trans or saturated fats. Yet all fats are loaded with calories -- and so need to be limited in our diet.
To make it even more confusing, labels boasting "zero trans fat" don't always mean a food is completely trans-fat-free. By law, such foods can contain small amounts of trans fats per serving. You'll still need to turn over the package and look at the list of ingredients and the nutrition facts panel.
So just what are trans fats? There are two types -- the naturally occurring type, found in small amounts in dairy and meat, and the artificial kind that results when liquid oils are hardened into "partially hydrogenated" fats. Natural trans fats are not the ones of concern, especially if you usually choose low-fat dairy and lean meats. The real worry in the American diet is the artificial trans fats, which are used extensively in fried foods, baked goods, cookies, icings, crackers, packaged snack foods, microwave popcorn, and some stick margarines.
These artificial trans fats started getting lots of attention after research showed that they could increase the risk for heart disease by increasing "bad" LDL cholesterol and decreasing "good" HDL cholesterol.
The American Heart Association (AHA) recommends limiting trans fat to less than 2 grams per day (a figure that includes the naturally occurring trans fats). The 2005 U.S. Dietary Guidelines simply recommend keeping trans-fats consumption as low as possible.
The Real Meaning of 'Zero Trans Fats'
In any grocery, you'll see many products boasting "zero trans fats." Yet this does not necessarily mean there is absolutely no trans fat in the product.
"Even though the label states "zero trans fats," one serving of the food can contain up to 0.5 grams of trans fat, according to the law, and still be labeled trans-fat-free," explains Elizabeth Ward, MS, RD.
The same guideline exists for saturated fats. Only when the food label states "no trans fats" does it really mean there are none.
The problem is that small amounts of these artery-clogging fats can add up quickly, especially if you eat several servings each day of foods that contain up to 0.5 grams per serving.
For example, popcorn can be an excellent source of fiber, is a whole grain, and can be low in calories. But if you eat several cups of microwave popcorn, the trans fat can really add up.
"Most people eat three cups at a sitting, which is three times the serving size and can have as much as 1.5 grams of trans fats," says Ward, author of The Pocket Idiot's Guide to the New Food Pyramids. "The same goes for trans-fat-free cookies that are easy to eat by the handful and add up quickly."
How to Find Trans Fats on Labels
The only way to be sure you're getting a truly trans-fat-free food is to check the list of ingredients on the label. Avoid products containing "partially hydrogenated fats or oils" (the main source of trans fats) or "shortening." Also keep in mind that some manufacturers are listing components of food ingredients separately so they can move trans fats lower on the list of ingredients.
Michael Jacobson, executive director for the watchdog group Center for Science in the Public Interest, suggests looking beyond trans fats when you're reading labels.
"There is a frozen ice cream snack that claims zero trans fat, yet has 20 grams of saturated fat in one serving," he says. "So even though it has no trans fats, it contains a day's worth of saturated fat and is anything but healthy.
"Trans fats are the worst fats, even more so than saturated fats, but you must evaluate a food on the entire profile, including calories, total fat, saturated fat, vitamins, mineral, sodium, sugar, and fiber."
Trans Fat Substitutes
If a label says trans-fat-free, what else might the food item have in it? Food chemists are experimenting with different fats and oils that are suitable replacements and don't alter taste or texture.
"Most of the fast-food restaurants have done a very good job switching to a vegetable oil like soybean oil to deep-fry their foods," says Jacobson.
Using heart-healthier monounsaturated or polyunsaturated oils, such as olive, canola, or corn oil, is a great option for some products, but doesn't work when you need a solid fat to make a food. Replacing trans fat with saturated fat is better, but not ideal.
"Trans fats are worse than any other fat, including butter or lard, so look for foods that use the least amount of trans fats," says Jacobson. "Even if it contains a little saturated fat, it is better than consuming the trans fat."
Adds Ward: "Tropical oils such as palm, palm kernel, and coconut may not contain trans fats, but they contain unhealthy saturated fats that are almost as bad for you as partially hydrogenated fats."
Trans Fats When You're Eating Out
But what about foods in restaurants, or from outside the U.S. where trans fat labeling may not be required? When restaurants and state fairs boast that their oils are trans-fat-free, some consumers may be misled into believing fried foods are good for them.
"Using trans-fat-free cooking oil to fry foods is certainly better," says Ward. "But the food is still fried, and fried food is high in fat and calories and generally not recommended for the heart or the waistline."
Wendy's, Taco Bell, Dunkin' Donuts, Baskin Robbins, Denny's, IHOP, KFC, Pizza Hut, and Starbucks are among the food companies that have replaced trans fats or are committed to doing so. Yet plenty of restaurants still use them.
"Avoiding fried foods and cakes, cookies, and pastries is the easiest way to reduce trans fat consumption when you eat out," says Jacobsen.
You can also ask about the type of fat used for frying, baking, and in salad dressings. Even if the menu boasts that items are "cooked in vegetable oil," that doesn't necessarily mean they're trans- fat-free foods. They may contain some partially hydrogenated vegetable oil.
Beyond Trans Fats
While eliminating trans fats is important, it's only one piece of the puzzle when it comes to protecting your heart and health.
"Trans fat is getting lots of bad press but it is important to keep in mind the 'big' fat picture, which includes total fat, saturated fat, and a healthy lifestyle," says cardiologist Robert Eckel, MD.
"Limiting trans fats is … only one component of a healthy dietary pattern that includes eating a wide variety of nutritious foods such as fruits, vegetables, and whole grains; limiting total fats [and] saturated fats; getting regular physical activity; and being at a healthy weight," says Tufts University researcher Alice Lichtenstein,DSc. Eckel, past president of the AHA, adds not smoking to that healthy lifestyle list.
To help educate consumers about trans fats and other fats, the AHA has launched a "Face the Fats" campaign, enlisting the help of Eckel as well as The Food Network's Alton Brown, known for his scientific approach to cooking. Brown uses his knowledge of food to help consumers learn to make low-fat substitutions that are nutritious and still delicious.
"I look at recipes and see how I can make it healthier by reducing the amount or type of fat, using a replacement ingredient, or altering the cooking method," says Brown. "But sometimes, none of these work and the answer is to simply eat a smaller portion."