Heatherton’s results did much more than provide additional confirmation that glucose is a vital part of willpower. They helped resolve the puzzle over how glucose could work without global changes in the brain’s total energy use. Apparently ego depletion shifts activity from one part of the brain to another. Your brain does not stop working when glucose is low. It stops doing some things and starts doing others. That may help explain why depleted people feel things more intensely than normal: Certain parts of the brain go into high gear just as others taper off.
