A few years back my brother got me into this "metabolic shift" diet that was basically 7 days of 20 carbs or less followed by one meal of "carb load". I did this diet twice and both times lost 17 lbs in a month. The problem was, I went mental, and turned into a total b*tch. I think it had to do with screwing with my blood sugar levels. I've been on straight Atkins for about 3 weeks and no problems with mood swings.