Even though I am not on Atkins, after watching my husband pickup on Dr. Fung, and doing 3- 36 hour fasts per week with amazing results on his bp, blood sugar and weight (he eats using CALP principles, as I do), I have moved from an easy 12/12 IF (12 hour eating window) to a 16/8, and now considering an 18/6 pattern (which I tried over this past weekend without any difficulty.)