If you are a parent, or know a parent, you have had someone claim that if their kid eats sugar they get 'hyperactive' - that may happen, but only because a child has been told they get hyperactive and act that way, the same way if you tell a child rum cake has rum they may act drunk.
Biologically, it doesn't work that way. Sugar can certainly help you if you are diabetic
(1) and "anti-sugar rhetoric is simply diet-centric disease-mongering engendered by physiologic illiteracy,”
according to Edward Archer, PhD.
(2)