Sure, this story is about the size of it, but it's really important when it comes to the size of the check is keeping its part. What is the difference? Serving sizes, most of which are listed on nutrition labels, refer to the number of servings in a bag or lunch box. For example, a snack bag of popcorn per serving: 130 calories, and bags, two servings of 260 calories if you actually spent in one sitting if you scarfed down the whole thing. Read the label and you proceed with caution because they consume far more than it bargained. More than looking for more ways to save calories? Check out these 25 ways to cut 250 calories Do.