When air-popped and eaten plain, popcorn is a healthy whole grain food. It is low in calories (30 calories per cup) and high in fiber (1 gram per cup).
A 3-cup serving of air-popped popcorn has only 9 calories, 1 gram of fat and close to 4 grams of fiber.
However, the minute you start cooking popcorn in oil or butter and adding salt and flavors, this can quickly turn it into an unhealthy snack.
The movie theater popcorn, which is popped in coconut oil with salt and "buttery topping" added has little to do with its clean-living relative, the air-popped, unflavored popcorn. A medium bucket of popcorn holds 20 cups and contains 1,200 calories, 980 milligrams of sodium and 60 grams of saturated fat, or about 3 days worth.
Most types of microwave popcorn contain fat and salt. Bagged, pre-popped popcorn has the same.
The best way to reap the potential health benefits is to make your own popcorn. A hot air popper works well but the air-popped popcorn can sometimes taste chewy because it absorbs humidity from the air.