Is corn a grain? How to classify corn on the cob, popcorn, corn flour

Corn takes on myriad configurations, from the classic corn on the cob to popcorn to more processed options including corn flour and corn syrup.

How, then, do you classify such a versatile food?

"Corn can uniquely be counted as either a grain and a vegetable, depending on the form," Washington, D.C.-based dietitian and diabetes educator Caroline Thomason, RD, CDCES, tells USA TODAY.

Whether you want to learn how to track your macronutrients, are following a healthcare professional's guidance to limit certain food types or are settling a corn-y bet, here's what nutrition experts want you to know about how to properly classify corn.

Is corn a grain?

The short answer is that whether corn is classified as a grain depends on its state.

"Corn on the cob is considered a starchy vegetable, while popcorn and corn flour are classified as grains," Thomason says.

But regardless of what form of corn you're consuming, it counts as a carbohydrate source and is "surprisingly rich in fiber," Thomason adds.

One ear of corn offers about 20 grams of carbohydrates, 2.5 grams of fiber and 2.6 grams of protein, according to the U.S. Department of Agriculture's food database. A bag of microwave popcorn, on the other hand, has about 47 grams of carbohydrates, 4.7 grams of fiber and 7.8 grams of protein. And a 100 gram serving of corn flour (which equals roughly 3/4 cup) contains about 77 grams of carbohydrates, 7 grams of fiber and 7.5 grams of protein.

Is corn actually good for you? Find out how healthy the summer staple really is.

Is corn OK on a low carb diet?

Regardless of its form, the fact that corn is a source of carbohydrates means that those who have been instructed by a health professional to avoid or restrict carbs should be mindful of their corn intake, as starchy vegetables and grains are both high in carbohydrates.

That doesn't mean corn is inherently bad for the general public, though. Thomason notes that it still provides essential nutrients including fiber, B vitamins and "antioxidants like lutein and zeaxanthin, which support eye health."

More: Corn syrup is in just about everything we eat. How bad is it?

She adds: "Whole forms, like popcorn and corn on the cob, offer more nutrients and fiber than refined products like corn syrup or cornmeal."

This article originally appeared on USA TODAY: Is corn a grain? A nutritionist explains