I was on an absolutely no carb diet that a nutritionist gave me and it was great, I lost weight, felt wonderful, and then bam I went total manic. My Pdoc said some carbs are essential to helping the brain function and that by me going completely carb free I triggered the mania. I don't know how true/valid it it (she didn't like my diet to start with) but I have been afraid to try again. I would love to find that balance point, but I am a scaredy cat and won't push the line.