I recommend everyone to read e-book by Neil Patel "What is disease" who in 2000 at the age 28 was diagnosed with a rugby ball sized tumour in his left leg, and told that even with a leg amputation and aggressive chemotherapy he had a 25% chance of being alive in five years.
It is the most profound little book I have ever read.
It gives you deeper understanding of what exactly disease is. It goes for almost any disease.
Here is the link to youtube interview with Neil Patel, but do read the book as well.It will become your health bible.
