One medium apple contains 95 calories, according to the USDA. A large apple has 116 calories, while a smaller one has 77 calories. It can also depend on the specific type of apple.
Most of the calories in apples come from sugar. A medium apple has 25 grams of carbohydrates, about 19 of which come from sugar, as well as 4 grams of fiber, according to the USDA. In fact, a medium apple has less than 1/2 a gram of protein and less than 1/3 a gram of fat. Carbohydrates, protein and fat make up the calories in any given food, but alcohol can account for some too.