It's easy to get answers about health and nutrition! Just send your question by email to firstname.lastname@example.org and Dr. Harlan will respond to selected questions of general interest. Answers will be posted in the Ask Dr. Gourmet newsletter (sign up now!) and archived in the Ask Dr. Gourmet section of the website.
If corn has calories, how come popcorn essentially doesn't? Where do the calories go?
The idea that popcorn does not contain calories is a myth.
100 grams of un-popped popcorn contains 375 calories, while 100 grams of popped has a similar amount at 387 calories. The difference is that 100 grams of un-popped kernels is about 1/3 cup and that will make a LOT of popped popcorn. Somewhere in the neighborhood of 13 cups.
Interestingly, popping corn is a particular type of corn with the kernels being tightly sealed - much different from the corn on the cob we eat. When they are heated the trapped moisture builds up and the kernels expand to about 15 times their original size. The kernels are much denser than yellow corn. A cup of yellow or white corn kernels of the kind we eat has only about 85 calories partly due to their much higher moisture content.
Not only is popcorn low in calories, it's really good for you. Three cups of air-popped popcorn has 4 grams of fiber but less than 100 calories. All the major popcorn companies now sell 100 calorie packs of microwave popcorn. This makes a great, filling snack that's tasty and good for you.
Thanks for writing,
Timothy S. Harlan, MD, FACP