Popcorn on its own is low in fat and high in dietary fiber. It makes for an excellent snack provided it is devoid of butter and oils. The only reason why popcorn can lead to abdominal fat is because it is covered entirely in butter, is over salted and cooked in high fat oils. It remains an excellent diet food if made with minimal oil and salt. Eating too much popcorn can cause abdominal fat. The butter and oils present will deposit in your abdominal in the form of fat cells. It's okay if you have popcorn in small amounts and don't make it a part of your everyday diet.