I see that the microwave popcorn kept as a failsafe in my desk drawer contains 20 calories per buttery cup. Sounds good, but watch out: the bag also informs us that the popcorn is 90 calories per serving when unpopped. So if you’re counting your calories and were thinking about ripping open a bag and crunching on fistfuls of raw kernels, think again. I don’t care how delicious it sounds.