If I had to boil down all the information known and consider what matters it would boil down to a. eat healthy which we now have many decades and many studies incorporating practically a billion people and all the research boils down to four principles 1. Stay away from all animal products 2. Generally stay away from all manufactured products 3. Eat a diet rich in greens, olive oil, and omega 3 ( found for example in chia) 4. A key component of health is to walk daily – To the extent possible destress – best way is to see the good in the bad ( for stress is fear and we fear bad) and obviously the purpose of life is to ignore societal mass stupidity or hysteria