I’ve actually noticed a correlation between sleep and stuttering. Days that I need to do an overnight shift and don’t get enough sleep, I stutter like crazy. If I let myself sleep, it lessens dramatically. I’m fairly certain it has to do with elevated levels of cortisol and overstimulation. Our nervous system is already constantly on edge and not sleeping just compounds to it. I’ve never really dieted but I can imagine it being the same. Especially with more strict diets. Your body needs sugar, oxygen, and rest. By limiting the sugar, it can definitely make you feel lightheaded, moody, anxious...in fact those are some of the main symptoms of moderate hypoglycemia.