Food companies are scrambling to replace trans fat in everything from french fries to cookies, but health experts worry that what's good for the nation's heart might be bad for its waistline.
Trans fat is created when hydrogen is added to vegetable oil. The resulting ingredient, known as partially hydrogenated vegetable oil, is what makes french fries crispy and croissants flaky. But trans fat's effect on cholesterol it raises the bad kind and lowers the good has made it a food-industry villain.
Ever since the Food and Drug Administration required food companies to disclose the amount of trans fat in their products last year, the industry has been searching for replacement ingredients. Kraft Foods Inc., the world's second-largest food manufacturer by revenue, has removed trans fat from numerous products, including Oreo cookies, Wheat Thins crackers and Jell-O pudding snacks. PepsiCo's Frito-Lay has eliminated trans fat from all of its chips.
So what's going in food instead of trans fat? Some food makers are going back to ingredients high in cholesterol-raising saturated fat, such as palm oil, palm kernel oil and coconut oil. In Kellogg's Eggo blueberry waffles, for example, trans fats have been replaced with palm oil and palm kernel oil, while Oreos now contain "palm oil and/or canola oil."
Kraft says that while the saturated fat content of Oreos is higher, the overall fat content is the same, at 7 grams per serving. "The effort wasn't just about removing trans fat, but about keeping the nutrition profile the same," says spokeswoman Laurie Guzzinati.
Thuy-An Wilkins, a spokeswoman for Kellogg, says the company has removed the trans fat in most of its products without increasing the amount of saturated fat, but it's still "a work in progress."
Other products are achieving trans-fat-free status through interesterification, a process in which fatty acids are redistributed on a fat molecule to make liquid fats behave more like solid fats. Products made with interesterified fat include Promise Buttery Spread and Enova cooking oil. Unilever, the maker of Promise, conducted its own study 10 years ago that found no adverse effects from food made with interesterified fat, says Doug Balentine, Unilever's director of nutrition sciences for the Americas.
But other nutrition experts say not enough is known about the safety of interesterified fat. There was little interest in researching the ingredient until the recent push for trans-fat alternatives. David Baer, a research physiologist at the U.S. Department of Agriculture's Beltsville Human Nutrition Research Center, says his own research has studied only blended fats and offers no insights on interesterified fats specifically. "We're interested in trying to figure out the health effects," he says. "The nutrition community is puzzled by what might be the most healthful alternative to trans fat."
K.C. Hayes, director of the Foster Biomedical Research Lab at Brandeis University, says that while the ingredient is in relatively few products now, its use may grow before the health-care community fully understands its impact. Dr. Hayes, who conducted a small study funded by the palm-oil industry that did find negative health effects from interesterified fats, says, "The point is, we should know more before we go off trans fat and onto something else."
The American Heart Association recommends replacing trans fat with monounsaturated fats, which are found in olive, canola, peanut and sunflower oils, or with the polyunsaturated fats found in soybean, corn and safflower oils. For instance, a lot of the chicken sold at KFC is now fried in a type of soybean oil, and McDonald's in the U.S. is switching to a proprietary blend of canola, soybean and corn oils for its french fries.
The biggest danger of the trans-fat swap-out could be that consumers will eat more junk food because they think it's healthier. For one thing, zero doesn't necessarily mean zero. Products can still have up to half a gram of trans fat and carry a "zero trans fat per serving" label. So if someone eats more than a serving of cookies, they could still be consuming a few grams of trans fat.