how many calories in a ruby grapefruit
Basic Nutritional Content. Half of a ruby red grapefruit provides 64 percent of the daily value for vitamin C, 28 percent of the DV for vitamin A and 8 percent of the DV for fiber. This serving only has 52 calories, most of which come from carbohydrates, as a grapefruit only contains 0.9 gram of protein and 0.2 gram of fat.