Melons make for a refreshing and lower-calorie treat during the warmer months. Most melons weigh in at under 50 calories per one-cup serving and contain fiber. Watermelons contain vitamin C and potassium, as well as a high water content, which contributes to hydration. Cantaloupe is an excellent source of folic acid, potassium, vitamin C and fiber. Honeydew melons are an excellent source of vitamin C. You can eat melon alone, or add it to smoothies, salads or desserts.