Fasting and Periods

Hello everyone. I’ve been on keto and IF for a little over a month. I started due to PCOS and obesity and have so far lost 9lbs since starting on February 6. However, my weight has barely moved after the initial loss of water weight and I’m concerned. My question is, has anyone who has done extended fasting experience period irregularities? I’m asking because I recently went to see my new ob-gyn who’s incredibly supportive of keto and IF (we found out we’re both on OMAD and he encouraged me to keep doing it) but advised against extended fasting because my period will stop. The absoluteness of that statement confuses me because I read that if you have a lot of excess body fat (I have about 72lbs left to lose) extended fasting shouldn’t affect your period and would actually benefit you. I’d appreciate any input. Thank you!

Answer

I have PCOS and irregular periods. I started keto and IF and extended fasting on Feb 17 so we’re basically twinsies, lol. I have spotted once and have had (frequent) small amounts of red/brown discharge on my TP.

I believe your Dr’s opinion on your cycle. When we are fasting (extended) our bodies are in survival mode and one of the components of that is to stop ovulation because if we were actually starving we’d be unable to carry a child. Basically growing a child would not behoove our starving predicament.

That said, once you and I are at our goal weights I have absolutely believe we will stay ovulating again.

Hope that helps, and since we’re twins, feel free to PM me if you need support.

Answer

Idk anything about PCOS but I was doing a 3 day fast and started my period which has been totally normal (except for no pain). In the past three day fasts have had zero to moderate effect on my periods… But it’s not like I’ve done a 72 hour fast consistently every week for months.

I will say that I did a dry fast 65+ hours and it changed my cycle completely. Likely from the hormones stored in fat cells.

I would say trust your doctor. Antedotally it seems fine for most but if you’re worried about losing your period then stay away from too many extended fasts.