Don't try the Carnivore Diet.

I've gone closer to paleo .. but still have some fat free greek yogurt, limited amount of cheese, and protein powder. Admit I'm struggling to give up the occasional couple slices of pizza, tortillas for tacos, a burger or breakfast sammie. Keeping the cheats to ~ once a week.

The problem with diets like that is that there is little research to back up the claims and so most of the claims are anecdotal and they are often made by people who are less than honest. Even if they are honest, it is of no particular scientific value that something works well with certain individuals when you have no idea which common properties or conditions they may or may not have. It's as useful as me determining that Pepsi makes my nails stronger. Whether true or not, it tells nothing about why or why not.

I'm mostly chicken and fish

I think I could handle it

I've been a Hypercarnivore ALL my life!

I imagine, at first, constipation would be an issue

I would never go on an all meat diet.

Is this the keytone thing?

Are you saying no meat?