Trans fats became popularized when Walter Willett, M.D., chairman of the Harvard School of Public Health’s Department of Nutrition, completed a study involving 80,000 women. His results showed that for every 5% increase in the amount of saturated fats a woman consumed, her risk of heart disease increased by 17%, while only a 2% increase in trans fats increased her heart disease risk by 93%. Additionally, Willett found that the risk of type 2 diabetes rose by 39% from only a 2% increase in calories from trans fats, whereas saturated fat did not affect diabetes at all.
While meat and dairy products contain small amounts of naturally-occurring trans fat, the majority of trans fat is created artificially by bubbling hydrogen gas through vegetable oil, a process called partial hydrogenation. This transforms some of the oil’s unsaturated fat (the “good” fat) into trans fat, which raises LDL (the “bad” cholesterol), just as saturated fat does. Worse yet, some studies have found that trans fat lowers HDL (the “good” cholesterol), too.
So why do many food manufacturers use hydrogenated vegetable oil with full knowledge of the serious health risks of trans fats? Easy — they’re great for the food industry — they keep foods from going stale so they can last longer on the shelves; they’re less expensive than butter; and they’re more stable, which is especially helpful for deep-frying foods.
But is trans fat really a necessary ingredient? “It is put into the food supply by the food industry and can be completely eliminated (the Europeans have almost done this) without individuals needing to make any changes in their diets,” said Dr. Willett.
However, most experts feel that an all-out ban is impractical. Instead, to combat this information gap, the Food and Drug Administration (FDA) is finalizing a plan that would require trans fat labeling on packaged foods, prompted by the Institute of Medicine, a government advisory agency that has conducted a number of studies on the health risks of trans fats.
Public awareness of trans fats is already making a difference. Frito-Lay told Consumer Reports that it plans to eliminate trans fat from Cheetos, Doritos, and Tostitos, and McDonald’s recently decided to cut out nearly half the trans fats from their French fries. Keep in mind, this reduction doesn’t suddenly make fast food a health food — taking out the trans fat doesn’t affect the calories — a super-size order of McDonald’s fries still has 610 calories.
In fact, many nutrition experts think the attention given to trans fats is “overkill” in that it narrowly focuses on only one area of a person’s diet. “I don’t think the issue is trans fat at all. The issue is healthy eating habits. How many Krispy Kremes [doughnuts] do you need to eat? What does this add to your diet?” asks Dr. Margo A. Denke, M.D., professor of nutrition at the University of Texas Southwestern Medical Center at Dallas.
Dr. Willett agrees that overall diet is paramount, but he cautions that trans fats still pose a formidable health risk: “The risks of obesity are worse than eating large amounts of any kind of fat. However, we see that the combination of obesity and high trans fat intake is a particularly bad one for risk of type 2 diabetes.”
So what is an acceptable level of trans fat?
“Because they are not essential and provide no known health benefit to human beings, there is no safe level of trans fatty acids, and people should eat as little of them as possible while consuming a nutritionally adequate diet,” said Barbara Schneeman, professor of nutrition at the University of California, Davis. “But I’m much more concerned about excess calories that are consumed — because almost as a matter of course items that contain trans fatty acids are high in calories [fried foods and bakery items],” added Dr. Schneeman.
The bottom line is a familiar one: consume as little trans fat and saturated fat as possible, and maintain a healthy weight. Most researchers recommend reducing your intake of saturated and trans fats to less than 10% of calories, or 20 grams per day of both fats combined.
Because the trans fat content is not yet available on most food labels, Consumer Reports and other health experts offer the following recommendations for identifying trans fatty acids: