Those recommendations would be the opposite of what doctors I follow would say. They would say more meat and less fiber. Me? I'm no doctor so my opinion does not count. I'll give a couple or a few links to what doctors I follow say. Use your own judgement. They basically say a person does not need fiber and it is an irritant in the case of IBS and other bowel problems and give some research to back up their claims.

https://www.youtube.com/watch?v=LGbpOtg9TQI
He talks about polyps and cancer at around 11 minutes.

https://www.youtube.com/results?search_query=dr+paul+mason+fiber

https://www.youtube.com/results?search_query=dr+paul+mason+diverticulitis

The Physionic guy if you want to listen to an argument against what Dr Paul Mason says (will come up in the search for Mason).

https://www.youtube.com/results?search_query=dr+ken+berry+fiber

https://www.youtube.com/results?search_query=dr+ken+berry+diverticulitis