One of the most used forms of propaganda 
Discussion
Tried and true. It is crazy to see how tightly people latch on to something they initially learned and how they will never allow those ideas be replaced.
Nutrition is one area where I see such a crazy resistance to change. Money is another one. It’s really sad and frustrating.
I’ve flipped on most things I held as true a decade ago. Thankful I have the plasticity to take in new information and change my mind.