Fact. Whole grains are products made from the entire grain kernel, including the bran, germ and endosperm. Refined grains have been processed to get a finer texture and longer shelf life, but that also strips the bran and germ. Popcorn comes from heating the entire grain kernel, and since nothing is lost in the process, it is indeed a whole grain.

Popcorn is a good source of fiber and, on its own, low in saturated fat, calories and cholesterol. The problem comes in how we make popcorn or what we put on it.

Popcorn popped in oil will be higher in calories and fat than air-popped popcorn, and adding toppings like butter, cheese, sugar and salt don’t help.

Air-popped popcorn contains only 30 calories per cup. Even a five-cup serving – the size of a children’s bag of popcorn – represents a pretty healthy snack at 150 calories and virtually no fat. And it’s generally the cheapest option. (Be wary of pre-popped bags of popcorn in the supermarket labeled air-popped, as many are sprayed with oil or butter afterward.)

Microwave popcorn can run the gamut from rather healthy to downright gluttonous. A recent analysis by the Center for Science in the Public Interest found that microwave popcorn labeled as ”light” or ”94 percent fat-free” generally ranged from 80 to 100 calories for a five-cup serving, with less than 2 grams of total fat. Regular microwave popcorn ranges from 150 to 230 calories, and three to five grams of saturated fat. Brands with sugar, cheese or extra butter topping trend toward the high end of the calorie and fat spectrum.

Most of the light popcorns also have a manageable amount of sodium. But other popcorn brands can have plenty.

Be sure to check the nutrition label before buying popcorn and make sure you’re comparing similar serving sizes from product to product. A full bag of microwave popcorn generally yields 10 to 12 cups of popcorn.

The center’s 1994 report on movie theater popcorn prompted many theaters to switch from artery-clogging coconut oil to more healthy canola or sunflower oil. But some theaters switched to partially hydrogenated canola oil that contains more trans fat than non-hydrogenated oil.

The monstrous serving containers also mean more total calories and fat. A large popcorn (20 cups) popped in coconut oil and topped with butter flavoring contains 1,640 calories and 73 grams of saturated fat. That’s a full days’ caloric total for many people and four days worth of saturated fat.

There’s also evidence that people eat more popcorn with the larger serving sizes. A Cornell University study gave 158 moviegoers either medium or large tubs of either fresh or 14-day old popcorn. The test subjects with large tubs ate 34 percent more of the stale popcorn and 45 percent more fresh popcorn than those with medium tubs.

– Markian Hawryluk