How is Terri Schiavo still living? Well she is getting fed, of course. There is no way someone in that condition could live without food and water for 13 days, is there? I would love for a doctor who really knows to e-mail me and explain how she is hanging on.
One thing I did remember that applies here is the German Army in Russia. How does that tie in, you ask? Well, as the German Army got surrounded in Stalingrad and the rations went down an interesting phenomenon began to happen. The strongest and largest soldiers started showing adverse affects from malnutrition and dying first. Of course virtually all of the Germans who surrendered died in Russian camps, but that is another post for another day.
If you are a larger or more muscular bound person, you consume more energy to keep your ship afloat. The smaller guys in the German Army were able to handle the smaller rations better for a longer period of time. I think this may be what is happening in the Schiavo case. She has been bed ridden for 15 years. More than likely most if not all of her musculature has decayed and it probably takes very little energy to keep her breathing and keep her kidneys functioning.
Unless someone is feeding her, which I think is exactly what is hapenning.