Snake will have new worries this time around. Out in the middle of the wilderness, rations are hard to find. That's bad news for the plant and animal life (bugs, fish, birds, etc.) that he comes across because now more than simply ambient life, they are essentially food. And eating is a necessity. Kojima will only hint that if Snake goes hungry for too long he will have trouble staying focused, but one can assume from his elusiveness that there could be more dire consequences. Having Snake hunt for his food is already an interesting diversion, but Kojima stirs things up by turning Snake into a Pokemon. Yes, Snake will have a large number of foods to choose from but he will develop a taste for certain types of foods. If he eats enough of them, he will become stronger.