You must obtain food but not from any one specific provider. No company will long "exploit" you (Hmm, where have we heard that term before?) unless they are protected from competition by a coercive state.
Read up on e.g. lives of miners in the United States in the past. It happened many times that a private interest controlled all your life - your housing, your food, your tools. Companies can, and if allowed will, create conditions where competing with them is impossible. One of the reasons we have states is to prevent exactly that from happening.