The increased appetite is because the body needs insulin to process the food you make into energy. So without the insulin your body cannot break down the food it eats so it thinks it is starving. So it wants to eat so it has fuel to run on.
This is also why you lose wieght, your body cant get the energy it needs from the food you eat so it starts to break down your muscles for energy. Thus you lose weight rapidly.
The sugar in the urine is your bodys way of trying to get rid of the excess sugar in your system. Without the insulin breaking down the sugar into fuel for your body it just gets passed around through the blood stream. The kidneys try to filter it out and pass it out of the body in your urine.
When sugar levels in the blood are high it thickens the blood. The higher the sugar levels the thicker the blood gets. When it is in the 500 to 600 range the blood is about as thick as ketchup. This damages the blood vessels and also causes alot of damage to your organs. It also make you hurt all over.. thick blood is painful.
