According to common scientific knowledge, the calorie content of a watermelon is the calorie content of the entire watermelon, including the flesh and the rind. Each 100 grams of watermelon has about 25 calories, a figure that is usually widely accepted and used.

However, in response to your question, if you were to calculate the calories from the flesh part of the melon only, the result would be lower than the value of 25 calories per 100 grams. However, this is not an accurate calculation because the flesh and skin parts of the melon differ in terms of nutrient content and calories. So, to get accurate results, you should calculate the calories of watermelon by including both the flesh and rind parts together.

Overall, if you want to know the number of calories added after eating half of a watermelon (8 pounds), you should multiply the weight of the whole watermelon (including the flesh and the rind) by the calorie value per 100 grams of watermelon (25 calories), and then divide it by 1,000, and the final result will be the number of calories added after eating half of a watermelon (in calories).