> What did the medical field do to earn such credibility with you?

For oncology? A whole lot. It's actually miraculous what they've developed to treat cancer. Cancer treatment has gotten so good that it's common for oncologists to caution against the 5 year study survival rates due to new and better treatments rapidly coming online. A 5 year study is necessarily 5 years out of date.

Medicine isn't a unified field. Having broad skepticism is an irrational position as there's a huge difference between the oncology field and the nutrition field.