how much fiber is in one cup of watermelon?
Depending on how you slice it, watermelon contains: 1  1 cup diced watermelon: 46 calories, 0.6 grams fiber, 11.6 grams carbohydrates. 2  1 cup watermelon balls: 46 calories, 0.6 grams fiber, 11.6 grams carbohydrates. 3  1 wedge of watermelon (1/16 of a watermelon): 86 calories, 1.1 grams fiber, 22 grams carbohydrates.