A one-third-cup serving of raw, seedless watermelon rind is now listed in USDA FoodData Central at 10 calories, with 1 gram of fiber, 140 milligrams of potassium and 4 milligrams of vitamin C.
The new entry gives dietitians and food-service operators standardized data for an edible part of the fruit that often gets discarded, as interest in rind recipes has been rising.
National Watermelon Promotion Board data show watermelons are about 30% rind and 62% of consumers throw that portion away—roughly 5 pounds on average—framing the move as a food-waste reduction effort.
Nutrition experts said rind is not a substitute for the flesh, which remains richer in nutrients such as lycopene, but it can be used in smoothies, slaws, pickles and stir-fries if the melon is washed first.