Top 9 Health Benefits of Eating Watermelon Watermelon is a delicious and refreshing fruit that's also good for you. It contains only 46 calories per cup but is high in vitamin C, vitamin A and many healthy plant compounds. Here are the top 9 health benefits of eating watermelon. Helps You Hydrate Contains Nutrients and Beneficial Plant Compounds As far as fruits go, watermelon is one of the lowest in calories — only 46 calories per cup (154 grams). That's lower than even low-sugar fruits such as berries ( 2 ). One cup (154 grams) of watermelon has many other nutrients as well, including these vitamins and minerals: Vitamin C: 21% of the Reference Daily Intake (RDI) Vitamin A: 18% of the RDI Potassium: 5% of the RDI Magnesium: 4% of the RDI Vitamins B1, B5 and B6: 3% of the RD Contains Compounds That May Help Prevent Cancer May Improve Heart Health May Lower Inflammation and Oxidative Stress May Help Prevent Macu...