Underfed (adj)
Definition: not getting adequate food
“Compared with the rest of us, they have sluggish and underfed brain reward circuits, so much of everyday life feels routine and understimulating.”
Encountered from A Natural fix for A.D.H.D
The author is saying that people with ADHD has a different way of thinking than people that don’t have ADHD so they do stuff that causes them to be a step behind.
https://www.vocabulary.com/dictionary/underfed