I would heartily suggest 90 minutes watching "Fat - A Documentary"
Pulls together everything about diet, where we have been misled and many other aspects in a brief but informative film.
Lots of our faves on it too (although unfortunately not the Unwins).
You can also rent via YouTube for £2.99......
Also I would highly recommend it - very well made.
On the vegan side have a look at Game Changers via Netflix.
Compare and contrast!