The number of calories in a piece of watermelon depends on its weight. Usually, 100 grams of fresh watermelon has about 30 kilocalories.
Therefore, for a piece of watermelon of about 500 grams (1 pound), its calorie content is roughly 150 kilocalories. This is a rough estimate and the actual calories may vary depending on the sweetness and variety of watermelon. Overall, watermelon is relatively low in calories and rich in vitamins and minerals, making it a good choice for a low-calorie diet.
However, it should be noted that patients with diabetes or poor blood sugar control should be careful in consuming it .