Ask The Doctor: Trans Fat Trickery

How can some food labels proclaim “0 grams trans fat” on the package and still list hydrogenated oils in the ingredients?
By Lisa Lanzano, RD

This is a great question, and one that confuses many people. If a food lists “partially hydrogenated” or “fully hydrogenated” oils in its ingredients, then it definitely contains trans fats, despite the “0 grams trans fat” claim.

Trans fat is created when food manufacturers make liquid vegetable oils solid by adding hydrogen (hence the name hydrogenated oil). They do this to increase the shelf life of the product, because trans fat takes longer than vegetable oil to spoil. Unfortunately, this process changes the natural structure of the oil, making it harmful to our bodies. A wealth of research has shown that consuming trans fat significantly increases your risk of cardiovascular disease by raising your total and LDL cholesterol (the bad kind), and possibly decreasing your HDL cholesterol (the good kind). Eating trans fat-loaded foods also increases belly fat, a sign of metabolic syndrome.

So how can labels promise “0 grams trans fat” when the food has hydrogenated oils? The reason lies in the rules set forth by the FDA. When a product contains less than 0.5 grams of trans fat per serving, the number on the nutrition label can be rounded down to zero. But this doesn’t make the product free of trans fat. That half gram per serving is still there. If you eat just one serving, even the FDA would have to admit you’re consuming trans fat. Couple that little sleight of hand with the fact that most Americans routinely eat more than the suggested serving size, and you’ve got two important reasons to choose your foods wisely.

Your best bet is to avoid trans fat altogether. It most commonly hides in cookies, crackers, microwave popcorn, margarine, and other processed foods. The next time you see a product boasting “0 grams trans fat,” check for hydrogenated oils in the ingredients. If they’re listed, steer clear of the food, and remember the old adage: caveat emptor, let the buyer beware.

What to Do?
1. When buying a new food, look at the Nutrition Facts box. Under “Total Fat,” you’ll see a listing for trans fat. If the number is greater than 0—be it 1 gram, 2 grams, or 20 grams—go to step three.

2. Now read the Ingredients box (usually below the Nutrition Facts box). If you find “hydrogenated oils,” “partially hydrogenated oils,” or “fully hydrogenated oils,” go to step three. If you don’t see these listed, the product is free of trans fat and fine to eat.

3. Don’t eat this food—it has trans fat. Check out organic or natural-food alternatives—they probably taste better, too!

Lisa Lanzano, RD, of Boulder, Colorado, offers consultations, phone coaching, and cooking classes (