[nil_pointer]

Fiber. Most all-meat diets suggest taking fiber or psyllium husk supplements for this very reason.

[mango7283]

Good for them then. I'm not sure why this is better than just eating vegetables in some capacity but that's not for me to judge I guess.

[nil_pointer]

It's for keeping your body in ketosis. High fat, moderate protein, and zero/very low carbs - which is why people diet this way.