I can do high level thinking for around 6 hours with just two scrambled eggs and a cup of coffee.
What I need is something to prevent me from context drift. /starts googling how many scrambled eggs are equivalent to the energy consumed by a data center. Google how many chickens are in the world.../
Consider that you can do this as a working day because someone else is plowing the fields that grow your food, probably burning stored energy in fuels for the process
We're sadly not that efficient. The 150kcal/6h=600kcal/day you've mentioned aren't enough, and it takes more than 600kcal to create 600kcal plus transportation into your home
Besides, we won't stop existing, so any math about "chatgpt uses X kW and so it's better than hiring another human" doesn't work out. The human doesn't stop burning fuels when not in use: any LLM usage is additional energy that needs to be generated while staying within CO2 budgets