Published: June 1, 2012 By

chocolate barThat chocolate bar you just ate may be harder to burn off than you initially thought.

While nutrition facts printed on food labels are regulated by the Food and Drug Administration, companies can present smaller serving sizes on nutrition labels, so a food’s negative nutrients — calories and fat — show up as a lower number per serving, says business professor Donald Lichtenstein.

Take a 2-ounce chocolate bar that has 200 calories. Manufacturers could make the serving size one ounce, so it cuts the calories per serving in half.

Because of this, even the most health-conscious consumers can be led astray, according to Lichtenstein who conducted a study on nutrition labels with colleagues from Colorado State University and University of Florida.

“The problem comes when people do pay attention, but they only pay attention to the calorie information and not the serving size,” Lichtenstein says. “Those consumers who are more health conscious pay attention to calorie information, but they don’t take the extra step to look at the serving size.”

His tip? Calculate the calories and fat for a reasonable serving size, so you are aware of the health benefits and detriments of the food you eat.