How about carbondioxide? I started to look it up but am running out of time.
As for them possibly living off the carbon that your body unfortunately has a hard time using, it makes sense to me, but we will have to find someone who has looked at them closer, I guess. As for us, I am thinking that it is very necessary to find an easily digestible form of carbon that contains enough to support our life and not leave too much floating around in our blood stream. The supporting minerals of potassium and sodium bicarbonate from food source (or from dnrsite.com as theirs are the energies of those minerals and very easily used by our bodies) will make our bodies combust it better. Oatmeal is bad because it is high in carbon, too high, and also high in silica. I get floaters in my vision almost immediately after eating it. Another one listed in Jensen's book is coconut cream. Has a good amount of fat, not too many carbs, and is easy to digest. Doesn't supply all the calcium that cow and goat's milk does. Whoops, have to go again.