Not that I really eat curcubits anyway, but just for general info...
Watermelon has a much higher and better spread of nutrients and amino acids than something like an apple.
For the same weight, watermelon has less sugar than apple, about 10x more Vitamin A, more vitamin C, more essential fatty acids and more magnesium, potassium, zinc and selenium.
The "Seven Deadly Sins"
Grains (wheat/rice/oats etc) . . . . . Dairy (milk/yogurt/butter/cheese etc) . . . . . Nightshades (peppers/tomato/eggplant etc)
Tubers (potato/arrowroot etc) . . . Modernly palatable (cashews/olives etc) . . . Refined foods (salt/sugars etc )
Legumes (soy/beans/peas etc)