Changes in Menstrual Cycle in Ladies Only Posted January 4, 2015 So, I started the Whole30 on January 1st. It is my second one and the first one had no effect on my menstrual cycle. I started three days into this Whole30 and that puts me at about 3 weeks early. Should I be worried? I see some people talking about late periods, but not early and certainly not this early.