I love popcorn but hate the calories. I don't eat the poison that comes with salt and butter nor do I buy popcorn in those dangerous self-popping bags. Since we became vegetarians eons ago, we stray from butter and salt. You haven't tasted broccoli until you've eaten lightly steamed naked broccoli. Yes, it takes some getting used to, but once you know how things really taste you can never go back to salt, fat, and butter-laden foods.
I usually buy loose popcorn from specialty markets in bags or jars and use brown paper bags to cook them in the microwave. I use bags that are the roughly the size of a Panera sandwich bag. The bag needs to be small enough to go round in microwave but large enough to pop enough for 2 to 4 people. I put a layer of popcorn in the bottom of bag, pinch the top up just enough to keep the kernels from escaping, shake until I think the layer is even and set microwave for 4 minutes. DO NOT LEAVE POPPING CORN. Sometimes it take 3 minutes, or a little more, for kernels to slow down. When I hear them starting to fizzle out, I turn oven off.
I have tried all varieties of popcorn and recently stumbled on White Cat popcorn. It is the best I have ever had. It is big and fluffy and seldom gets stuck in your teeth. It has an amazing flavor that I love. You have to try it! Yes, you can add some salt and butter but you won't know what you are missing.