I'm not great on sources, sorry. I read stuff, absorb it, forget the origin. I do recall the strength of the sources though, and both claims are backed by pretty strong sources, especially the fibre one. Cancer might be from first principles and plus the weakness of the evidence of cancer risk, which has problems in methods, but even with those problems only managed a hazard ratio of less than 2. Real effects typically have hazard ratios over 4

If you search in this community you'll probably find posts about each of those topics

You may need to read research papers as this is a pretty science heavy community

The YouTube videos posts are typically by MDs with clinical experience with keto and carnivore, most are pretty short, and all have AI summaries