It is so hard to gain weight as a carnivore. I have to seriously overeat to even gain a couple pounds. And one day of slip up, I lose the weight gain. It's like the inverse of the standard american diet.
Hard to gain fat but hard to gain muscle too...
If you look at a plate with a cheeseburger and fries, chances are only 1/3rd of the calories are from the meat. If you pass on the bread and fries, etc, no one is used to eating 3 burgers (and you don't really need to do so either)!
It's pretty wild how most of the people around me are technically obese. Meanwhile I'm out here breaking my old highschool 5k times.