Ever wonder why your French fry container says zero grams of trans fats and not--No trans fats? Well, believe it or not, zero is not none. Read on to find out about the new math in your food.

Actually, it isn’t the new math. It is just the miracle of rounding. Under an FDA rule that took effect in 2006, if a serving of a food contains less than half (0.5) of a gram of trans fat, the label can indicate zero grams of trans fat. But, what is a gram? A gram is a metric unit of mass that is commonly used to express weight. Practically speaking a gram is about the weight of a pen cap.

A food manufacturer must report how much fat is in a single serving, but manufacturers often alter the serving size so that the amount of trans fat is below half of a gram so they can say that they have zero grams of trans fat. While not every food producer has decreased their serving size so that the trans fat level drops below 0.5 grams, some have. A small bag of potato chips may have zero grams of trans fat per serving, but this small bag may have two or more servings inside. If you eat more than one serving, you don’t really get to multiply the number of servings by zero to get the true amount of trans fat. Actually, if you eat over three servings of a zero grams trans fat food, you could be getting 1.5 grams of trans fats. Furthermore, throughout the course of a day, multiple servings of various zero grams trans fat foods can really start to add up. It is amazing how 0 + 0 + 0 + 0 + 0 can equal more than 2 grams of trans fat.

The important issue is that no amount of trans fat is considered safe. Trans fat cannot be used in the body to make energy like other fats, so these trans fats end up in the bloodstream--raising bad cholesterol (LDL), lowering good cholesterol (HDL), and depositing fat in the cell membranes of blood vessel walls where they makes arteries more rigid and lead to atherosclerosis, heart disease, and stroke. Because no amount of trans fat is considered safe, you should eat as little trans fat as possible. The American Heart Association recommends that people limit their trans fat to less than 2 grams a day, but the less you eat, the healthier you will be.

The problematic trans fat comes from the hydrogenation and processing of oils. If an ingredient list contains hydrogenated or partially hydrogenated oils, this means the product contains trans fat. So while the label may advertise zero grams of trans fat (per serving), if the ingredients include hydrogenated oils, then zero is actually some, So don’t be fooled by the new math--just say no to trans fats.