Buttered popcorn has 535 kcal and 31 g fat per 100 g. The butter roughly doubles the calories versus air-popped. A medium movie-theater bucket can hit 600–1,000 kcal before any toppings — cinema portions are deceptively calorie-dense.
How should I track Popcorn, buttered?
Popcorn, buttered is high in fiber. When it comes to Popcorn, buttered, weighing beats counting every time. Snack pieces vary in size, and a handful from a bag can easily be 50–100% more than the label serving. Research (Almiron-Roig et al., Appetite 2013) shows that people consistently underestimate portions of calorie-dense snacks. Another common trap: multi-serving packages. The label might show 150 calories "per serving," but if the bag contains three servings, you are really looking at 450 calories. Always check whether values are per piece, per serving, or per package.