What mistakes did Chris McCandless make that led to his death?

The most simple answer to this question is that Chris McCandless starved to death. It is undecided exactly why he starved however. In his book "Into the Wild," John Krakauer implies that a toxic alkaloid was present in seeds (named Hedysarum alpinum)McCandless which caused him to be unable to digest food and therefore starve. Since this theory was presented a number of contradictory theories have been suggested, for example that a different fungus R. leguminicola managed to grow on the seeds McCandless ate. Despite all this, a lot of forensic data states that Chris simply starved in the most basic sense, from lack of food.