What is your purpose if doing this type of diet? This is the first question you have to ask yourself.
Most of the time, people want to lose weight.
The only way to lose weight is calorie deficit. No fancy word, no fad diet, no short cuts. Just eat lesser calories than your TDEE
If you do this carnivore diet but your intake is 3000 cals per day, you still will get fatter
if you do it but your intake is 1200cals, you probably will lose weight
all these keto, LCHF, int fasting, carnivore, military.. all boils down to : Can you sustain this type of lifestyle/eating habit? If not, it will just be a matter of time before you give up and all will be back to square one