I am under the impression that refined sugar interferes with the optimal functioning of the brain, in addition to skewing a person's energy level, but I don't h

I am under the impression that refined sugar interferes with the optimal functioning of the brain, in addition to skewing a person's energy level, but I don't have citations or anything. It's a just info that I internalized as a child, from a family member who works with children who have learning disabilities.