I had a very interesting discussion with my friend regarding eggs and their connection to saturated fat which led to him quoting Dr. Michael Greger on how cross sectional studies being used to examine the connection between saturated fat and cholesterol levels are mathematically suppose to fail. Dr Greger cites some very old sources, now I don't know if these sources are ignored because science has changed or if we ignore them because big named companies with their own agenda had studies done to cover them up.
In my mind I'm thinking, if I make 100 people increase their egg intake a day and I compare their individual cholesterol levels from the beginning to the end how could that not show the effects that eggs have on cholesterol levels.
With my current knowledge it is difficult for me to understand this, here are the links to the videos below. Please help me understand his point of view. I am somewhat suspicious because he does have his own personal agenda, but I do want to understand his thought process.