A pomelo is a type of citrus fruit that is native to Southeast Asia. It is the largest citrus fruit and can range in size from grapefruit to watermelon. Pomelos have a thick outer rind and a segmented, juicy flesh that can be white, pink, or red. They are commonly eaten fresh, and are often used in salads, jams, and drinks. Pomelos are high in vitamin C and antioxidants, and are low in calories.