En español | Serving sizes can be sneaky. You think you’re watching your calories by glancing at the nutrition information on the back of your favorite food or beverage, but beware: If you don’t read carefully, you could be taking in four or five times the calories you think you are.

Take, for example, that bag of Bear Naked Banana Nut granola that you like for breakfast. Pour yourself a medium bowlful and you could be eating as many calories and grams of fat as a McDonald’s double cheeseburger. That’s because the actual serving size is only 1/4 cup (a mere 4 tablespoons) and 140 calories. Pour a whole cup’s worth (which is easy to do) and you’re eating 560 calories and 28 grams of fat.

One tiny sliver

Or how about that big four-cheese DiGiorno thin crust frozen pizza you brought home for dinner? The serving size is one-fifth of a square pizza. But, really, who eats just one-fifth of a pizza? And let’s not even talk about trying to cut a square pizza into five equal portions.

Because of these kinds of problems interpreting the fat and calorie information on food labels, the Food and Drug Administration is trying to figure out how to make labels more useful and realistic. Among other things, it is debating whether or not to change serving-size guidelines.

Should it increase serving sizes to reflect how Americans really eat, no matter how unhealthy that might be? Or should it keep the serving amounts the same, but force food companies to do a better job showing how many calories are in that giant bag of chips that you’re consuming all by yourself?

FDA spokesperson Siobhan DeLancey says the government is considering changes to nutritional labeling in conjunction with first lady Michelle Obama’s initiative on childhood obesity.

In addition, the U.S. Department of Agriculture will issue new federal dietary guidelines this year, which also may affect nutrition labeling.

“This is part of a greater nutritional initiative and a big focus for us,” DeLancey says. “FDA Commissioner Margaret Hamburg is very game to make packaging easier for people to read and understand and easier to use.” Among the issues she says the FDA currently is debating is, “If we increase the serving size, does that give people permission to eat more?”

Part of the problem, DeLancey notes, is that people don’t flip over the package and look at the nutrition facts. “That’s the key. If you want to eat it all, you just have to do the math.”

A 2008 FDA survey found that fewer than half of Americans check the label for calorie information, while 34 percent rarely or never check the calorie count. In addition, a recent Lempert Report survey of 1,305 supermarket shoppers found that nearly 80 percent find serving-size labeling information confusing.

This comes as no surprise to dietitian Bonnie Taub-Dix, a national spokeswoman for the American Dietetic Association. “People would like to ignore serving size. Who wants to see that the serving size is only one cookie?”

She says she believes the problem isn’t with the numbers in the nutrition facts, but that people don’t multiply those numbers by how many servings they actually consume.