Popcorn has become quite the favorite low calorie snack among dieters. Unfortunately, microwave popcorn, the most convenient way to make this healthy snack, is really bad for you. Diacetyl is a natural product that, in combination with acetoin, gives butter is characteristic flavor. It is added to almost all artificial butters, including those used in microwave popcorn, to give them a “real-butter” taste. Diacetyl, though natural, can also be dangerous. Many microwave popcorn manufacturers are voluntarily removing diacetyl from their products. Unfortunately, new evidence is arising that the product used to coat the bags, something called perfluorooctanoic acid or PFOA, is also toxic. If you want to have popcorn, the best thing you can do is go about it the old fashion way. Cook it in a pot with a little oil and add only a little butter and salt.