Is popcorn a diet food?

Popcorn is high in fiber and can indeed help you shed pounds.  The fiber in popcorn will help you end hunger pains.  Popcorn digests slowly and stays in your system longer and will help you feel fuller longer.  In certain studies, popcorn has been found to be more filling than  peanuts or a candy bar.  The candy bar because it is loaded with sugar and sugar is easily absorbed and stored in the body.  Popcorn will also help to build energy and improve your mood.
An air popper will be your best bet.  Popcorn from an air popper contains approximately 30 calories per cup.  Feel free to add some seasoning to it like seasoning salt or a dash of cayenne pepper for a bite.  If you prefer the easy micorwave popcorn, be sure to check the calorie content in each cup.  It could fool you and you could gain instead of lose.  I prefer the pops that say low calorie and low or no fat.  Try to stick with one that has about 20 calories per cup.