Ok, I have a small quibble with the statement that it isn't possible to limit one's self on popcorn. I normally do not get snacks at movies, but one time I did. I bought a small popcorn with butter and specifically ate a small amount (guessing about a half-cup), then gave the bag to other family members. Hubby had about a half-cup, son had about a half-cup and daughter, who was not low-carbing at the time, ate what she wanted of the rest.

If YOU can't stop, can't regulate the amount of something, then obviously it should be avoided. But, if you're strong enough to regulate, enjoy the appropriate amount. I have discovered a few things against which I am helpless and I do strictly avoid those things. Popcorn is not one of them.