No. Popcorn is actually healthy (depending on the kind). Eating popcorn without butter is actually a very healthy snack. It’s high in fiber and relatively low calorie. However, if you are buying popcorn that comes in a bag and flavored with butter/oil then it is not healthy. Popcorn makes a great healthy snack but remember if it’s covered in butter it is going to be full of fat and cholesterol.
Conclusion: Unflavored popcorn is actually healthy, but avoid buttery popcorn which is not.