Too many carbs and/or sugar will make me very tired and I can't think clearly but I'm also diabetic. I'm careful with carbs and limit myself as to how much I eat of them. I do eat carbs because this is where your energy comes from and your body does need some carbs but I don't overload on them.
I'm an avid label reader so I know what I'm putting in my mouth. By the way, when reading labels, the carbohydrates include the sugar in it's number.
Sherrine