The truth, in this case, is somewhere in the middle. Overall health is connected to nutrition. Most diseases can be prevented, or at least mitigated, by getting the right nutrients. Some diseases can be treated with natural remedies, and I do think that Big Pharma has no interest in putting for actual cures for certain diseases that are very profitable to treat (cancer, e.g.).

With all of that being said, if you have a life-threatening illness and you don't go see a doctor, you're just a fool. Even if it's true (and it is) that big Pharma is full of greedy, corrupt, government-connected f***s, most of the people who work in the sciences actually are trying to make peoples' lives longer and better, and many great cures and treatments have been developed by them. If you have a serious health problem, then you're a fool if you don't avail yourself of that.