Changes in Menstrual Cycle in Ladies Only Posted February 7, 2017 On 8/5/2013 at 2:27 PM, malie said: The exact same thing happened to me during my Whole30 (I'm on bc too), and that "extra" period lasted 18 days! Worst. I went to my doc for some tests and she found nothing wrong. I'm sure it was the diet changes. My next, most recent, period was a bit irregular but nothing compared to that 18-day one. Seems to be evening out now. I am also in the same boat despite being on the pill, and thought it might just be me. I finished my period before starting Whole30, but here we are a week and a day later and I am having a more intense period. I remember this happening the first time I did Whole30 and thought it was a fluke, but clearly my uterus does not prefer the shock of Whole30.