I think that my body got so used to sugar and carbs as our energy source that when I stopped it cold Turkey (pun intended) it was in desperate search and the reaction to something wrong in the body is often a headache. But once my body got used to the protein source (3-4 days) I felt great. The reason behind the carb. making you feel good, makes sense, a quick fix. But the vitamins and the water are very important to me, the water is becoming second nature to me now, and I'm getting better at remembering the vitamins, if I don't my legs ache.