A Guide to Trans Fats

Food label

Regulations from the Food and Drug Administration require food manufacturers to list trans fats on products that contain 0.5 grams or more of the unhealthy oil. Scott Olson / Getty Images hide caption

itoggle caption Scott Olson / Getty Images

KFC has joined three other chain restaurants in eliminating trans fat from their menus. Chili's, Wendy's and Ruby Tuesday recently dropped trans fat, an artificial hydrogenated fat which increases the level of bad cholesterol in the bloodstream.

KFC made the announcement the same day New York City held its first public hearing on the cooking oil. The city is trying to ban trans fat in restaurants, which often use the unhealthy oil to make fried foods and baked goods.

Denmark and the city of Tiburon near San Francisco have already banished trans fats from all local eateries. Other cities, such as Chicago and Los Angeles are weighing a switch to a healthier, soybean — or canola-based oil.

Why does the health world hate trans fat so? We talked to three public-health researchers about what consumers need to know about the shortening.

What is trans fat?: Trans fat is made when hydrogen is added to vegetable oil — a process invented in the late 19th century to help lengthen the shelf life of food products. The added hydrogen also makes frying oil last longer.

Why it's bad for you: Partially hydrogenated oil "raises the bad blood cholesterol (LDL) while lowering the good cholesterol (HDL)," says Marion Nestle, the author of What to Eat and a professor in the nutrition department at New York University. "It's worse than saturated fat because it's introducing something unnatural into the body. There's no reason to have trans fats in food. They're unnecessary, artificial and demonstrably bad."

Where it's found: According to the Food and Drug Administration, trans fat can be found in products such as cookies, crackers, vegetable shortenings, some margarines and snack foods. Just look for the phrase "partially hydrogenated oil" on the label. As of Jan. 1, 2006, all food manufacturers are required to label trans fat in their products.

Why food companies like it: One of the reasons food companies like partially hydrogenated oil is because they can use the oil again and again in the deep fryer, says Jeff Cronin, the communications director for the Center for Science in the Public Interest, a non-profit advocacy organization that sued KFC in June for using trans-fat-laden oil in the deep fryers.

Using trans fat saves money, says Cronin, but more importantly, the process saves the employees from continually changing the cooking oil, which often splatters. He points to a common myth: changing the oil to a non-trans fat will changes the taste of the product. Other factors, such as varying ingredients and cooking styles, are more likely the reasons for the taste difference. For example, baked potato chips do not have the same taste as fried potato chips.

Why it's on the wane in store-bought goods: "Once the FDA required food manufacturers to label their products, everyone managed to find a substitute," says Nestle. And no matter what fat they use, it's not nearly as bad as trans fat, says Walter Willet, chairman of the Department of Nutrition at the Harvard School of Public Health.

"Even substituted fat would still lead to a reduction in deaths from heart disease," Willet says.

The best health option is switching to an unsaturated fat, which helps lower cholesterol. Food manufacturers are slowly beginning to make the switch to these unsaturated fats. Look for monounsaturated or polyunsaturated fats on the label, which indicate healthier oils such as olive, sunflower and soybean.

Wendy's has switched, McDonald's has not: Wendy's is the only one of the three big burger chains that has made the switch to trans-free oils, says Cronin.

"McDonald's promised to make the switch in 2002," he says. "They were sued in 2004 by the American Heart Association and had to donate $7 million to promote banning trans fats. They still have not made the switch."

Other chains — such asChili's and Ruby Tuesday — fry their foods in trans-fat free canola oil.

But McDonald's is still using trans fat products.

When asked to explain its position, McDonald's said in a written statement that it is researching oil alternatives, and that the company's "priority is to also meet our customer expectations for taste and quality."

Surprise! It's still in some store-bought products: Even if a label says a product has zero grams of trans fat, it may not be true.

Under FDA regulations, "if the serving contains less than 0.5 gram of trans fat, the content, when declared, shall be expressed as zero." Food products, such as crackers, could contain .49 grams of trans fat and not require a label. You can eat a serving of crackers (from 5 to 15 crackers, depending on the brand and definitely not unusual for snack food) — and still get trans fat. Two servings that might seem to have no trans fat could actually have nearly a gram. And any amount of trans fat –- even in trace quantities -– can increase your chances of developing heart disease.

So to find out if a product has even trace amounts of trans fat, look at the ingredient list. If the ingredients list the words "partially hydrogenated vegetable oil," "hydrogenated vegetable oil" or "vegetable shortening," the food contains trans fat.

Waiter, is that a trans fat in my fry? When dining out or buying goods at a bakery, you won't know whether you're consuming trans fats unless you ask. And you won't really know unless, as Willet suggests, you ask to see the label for the fat that restaurants choose for frying. It should not have the words "partially hydrogenated vegetable oil," "hydrogenated vegetable oil" or "vegetable shortening" anywhere on the label.

It might be a little embarrassing to grill the waiter, but Willet thinks you should persist. "It's really good to do that," he says, "because it helps educate the restaurants, as well. A lot of them don't know they're using trans fat."

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