What does krakauer speculate happens to Chris in this chapter?

Before July 30, there is nothing in McCandless’s diary to hint that he is in anything but good health, if a little undernourished, but on July 30 he writes that he is extremely weak and having trouble even standing up. There are several theories as to what caused the change. One food that McCandless has been taking advantage of is a kind of wild potato, but by mid-July they might have been becoming too tough to eat, and it’s possible he started ingesting the seed pods of the plant instead. In addition, there is a kind of wild pea that looks very similar to the potato, but is poisonous. Krakauer believes that the former was the case, as McCandless had successfully eaten the potato for weeks without mistaking the pea for it, and there is a picture showing him with a bag of seeds—he even writes in his journal that his illness is the fault of the “pot. seed.”