Keto is wack as shit lol, your body does not really want to use ketone bodies. That's why they're primarily produced under very physiologically stressful conditions (prolonged starvation, poorly treated type 1 diabetes, etc.). It's your body's last resort to get energy from somewhere. Don't push your body to that point.

I also think "calories in vs calories out" is another wack myth in nutrition/fitness that's constantly propagated. not all calories are the same. 30 calories of protein is different from 30 calories of complex carbs and your body deals with them in different ways. I don't trust anyone who tries to oversimplify metabolism