I answer as someone who did 100% strict zero-carb carnivore for >1.5 years.

Keto/carnivore works well for fat people. They tend to lose their appetite once they are in ketosis and get leaner without feeling starved.

However, this effect disappears once you're in the 15-18% body fat range. Then it becomes hard to maintain a caloric deficit because of the lack of volume and fiber.

Pic was me in the middle of my carnivore diet. I looked big but not as lean as I would like.

The carnivore diet has other benefits, like zero teeth rot, you're never bloated, and you rarely fart. I think it also protects you from cancer.