All carbohydrates are sugar but unfortunately they contain enough of the essential nutrients you cannot get from fat and animal proteins alone.
There will be plenty of comments that will follow about how you don’t need any more essential nutrients other than what animal proteins can provide and how comfortable they about the abundance of MicroRNA’s building up in there colons and intestinal tract from animal proteins that are their for the purposes of causing cancer in humans to slow down over-population of humans (that high curve and then steep decline of a species who eats too much of the other on a statistical or actuarial chart?) and without resistant starch (not a carb for your body but food for your ketone producing microbiome protecting your gut lining from MicroRNA’s?) to clean it up and reverse it, your pretty much another number on a toe tag in the cold fridge down stairs. Microbiome that produce ketones kill gastrointestinal cancer causing MicroRNA’s and you can only do that by eating resistant starch from plants or there roots!
Any species that tries to live off one or more of any essential nutrient and subtracts the others will go extinct and die of malnutrition.