[pmayrgundter]

Main points are that brain takes ~20% of body's Base Metabolic Rate, and that active thinking takes 5% more than BMR.

Whole body context: - Base Metabolic Rate (awake): ~1.0-1.1 kcal/kg/hr - Deep Sleep Metabolic Rate: 0.8-0.9 kcal/kg/hr

CG says brain follows this as well.

So it suggests brain power use varies from 0.8 minimum to 1.1, with an extra 0.05 for thinking. This supports ideas that thinking is a relatively minor brain function, at least energetically.