Trans fat ban lowers trans fat consumption. And?

A study just published in the Annals of Internal Medicine has reached a somewhat tautological conclusion: Following restrictions on the use of partially hydrogenated fat (trans fat) in New York City chain restaurants, the trans fat content of patrons purchases decreased. Well, okay. But does this fairly predictable result translate to improved health among New Yorkers? That s far from clear.

The Bloomberg administration s policy, which went into full effect in July 2008, is based on the idea that a diet high in trans fat increases a person s risk of coronary heart disease. Yet this assertion is problematic, given that dietary fat in general has been found to have little effect on coronary heart disease. As ACSH s Dr. Elizabeth Whelan points out, the three major risk factors for cardiovascular disease are cigarette smoking, high LDL (bad) cholesterol, and high blood pressure. Fat, even the partially hydrogenated vegetable oils once ubiquitous in New York chain restaurants, is not the culprit.

Unfortunately, as many health experts have observed, the trans fat taboo has resulted in a misleading heath halo effect that s been a boon to the food industry but little help to consumers. As Dr. Alice H. Lichtenstein, editorializing in the Annals, points out, The major public health challenge in the U.S. is excess energy intake, and the question remains about whether the trans fat-free designation confers an undeserved health halo for foods that are high in energy and low in nutrient density.

If Americans are inclined to eat more of something because it s been marked trans fat-free, the real problem is thrown into relief: excess calories that lead to excess weight. Perhaps a better question might be whether patrons of those New York chain restaurants are actually consuming fewer calories.

"However," ACSH's Dr. Ruth Kava adds, while Dr. Lichtenstein is certainly correct about the possible health halo effect, it s still the case that getting people to stop smoking is a more important public health issue than over-consumption of calories. Furthermore, researchers will be hard-pressed to demonstrate a health benefit from the ban on trans fats in restaurant foods, even if there were one.