My partner decided to go on a rather drastic diet (from the way she used to eat) and cut out almost all sugar and refined carbohydrates and fast food and is on a 1500 calorie a day mostly meatless diet now. For the first three to four weeks she had panic attacks and thought she was dying, would cry etc. now - about 2 months into it - she is fine - more energy, better sleep, more exercise etc. She believes it was the loss of sugar and just general detox. It was horrible for awhile - like watching an addict dry out -but she is much better now and sticking to her new regine with renewed enthusiasm.