Achieving adequate calorie intake on a carnivore diet can be challenging due to insufficient fat consumption relative to protein intake.

“and I think the trick with gaining weight as far as I can tell is getting enough protein getting a surplus of protein getting enough leucine which is easy on a carnivore diet and getting enough calories and I think the problem for a lot of people on a carnivore diet is it's hard to get enough calories unless you eat fat a lot of us are not eating enough fat but if people wanted to gain weight if they wanted to gain muscle on a carnivore diet my thinking is eat a heck of a lot of fat”