I started fasting 3 days a week about 2 weeks ago (not quite ADF, but fasting T, TH, Sun). I’m now two weeks late (and confirmed not pregnant).
I couldn’t find a ton of info about this, so I wanted to share and see if others had similar experiences.
I usually have very predictable and on time cycles.
I know that Mindy Pelz on youtube doesn’t recommend fasting the week before your cycle as she believes it to have a negative effect on hormones and cycles, and she’s very pro-fast at all other times. I’ve heard conflicting reports from other sources, some say they fast every day (like OMAD) and their cycles corrected themselves after a few cycles. I’m in my 40s so fertility isn’t an issue for me anymore, but I know that these systems have impacts on so much so I’m wary of rocking the boat too much so to speak. But if I was still in my peak fertile years I would be even 10 times more cautious.
I think in those cases you’d be ok with a daily time restricted eating window that last cycle week but I wouldn’t be doing like 36 hour fasts.
I had this issue a few years ago when I started fasting I scoured Google and these threads. The closest thing to an explanation I could find was this (and I have no credible sources to back it up)..
Estrogen is held in fat cells. When we fast/go keto we are using fat for fuel and burning it up quickly. This floods our system with hormones which may temporarily alter our cycle.
You’re experiencing hypothalamic amenorrhea secondary to fasting. When the body is stressed it goes into survival mode. Shutting down non-essential functions such as reproduction. By itself or coupled with strenuous exercising, this will cause you to lose your period.
See your provider for more information. But basically you are in a low-estrogenic state due to stressful conditions.
Entering a routine of fasts can put a lot of shock on your body with unseen risks such as infertility. Please see your provider with concerns of amenorrhea.
This is actually a good sign. Believe it or not but women are not supposed to have their mensural cycle every month. It’s unnatural and a direct result of the amount of chemical growth hormones in the foods we have been deceived to consume by various cooperations and industrialists. These chemical growth hormones speed up the processes in the body in an unhealthy way. That’s why so many young children are beginning to develop so fast and experience sicknesses unheard of by earlier generations. In fact many women who choose to eat better and fast say that they are missing their period. Take this as a positive indicator that your health is improving and no you are not losing your fertility
Honestly, I don’t think it’s a cause-effect type response. I’m also 33f. Fast whenever, but ideally the two weeks after my period just because the week before and during I’m so hungry.
Fasting 3 days one time would have a very, very, very small chance of impacting your Hormonal cycle to that degree unless there’s something else going on. If I were you, I’d look for other potential causes.
Edit: I read it again and it looks like you may be doing this weekly.
Consistent fasts might have more of an impact. Especially if it’s brand new and you’ve never done any sort of fasting before. But it is still a relatively rare thing, from my experience and those of other women I’ve interacted with that fast.
Unless your body fat percentage is already very low.
Or unless you’re doing a severe caloric restriction on non-fasting days.