Is intermittent fasting safe for women?

Hi, This past month I have started time restricted eating in an attempt to start loosing weight. I am a 32 year old female, 5 foot 7, 170lbs. With my work schedule I usually fast between 6/7pm to 9pm most days, so am fasting roughly 14 to 15 hours. A couple of weeks ago I tried 2 19 hour fasts on the week during ovulation (days 12 to 18 for me). After this I experienced spotting and light bleeding for a week leading up to my period. I am normally very regular, this has not happened to me before. I was wondering if the IF could have tanked progesterone at this part of my cycle and caused the bleeding? I stopped fasting for the week leading up to my period, and my period has happened as normal thankfully. Has anyone else experienced hormone disruption due to fasting, similar to what I have just experienced? Can anyone suggest a work around? I have done similar fasting schedules in the past and find this a far easier way to lose weight than to restrict calories or food groups. I lost my periods in 2021 at 130lbs, but I think a lack of calories more likely caused this than IF. I really want IF to work for me and to not be at this weight anymore.

Answer

I started doing intermittent fasting is November when I weighed about 133 pounds. I mostly did 16:8. I am now on the slender side (5’6” 123#) with 14% body fat. I’ve shortened my fasting window to 14 hours because I am not trying to lose any more weight and would not mind gaining a couple pounds.

My cycle was 10 days late this month. It was also late the month before that, but I was really sick during October so I attributed that to the illness.

I think the lateness this month is attributable to the quick weight loss & my low body fat, not fasting but caused by calorie reduction facilitated by IF. But I could be wrong! You are not under weight, so I wouldn’t worry that you’ve done anything to mess with your cycle long term. It might just be an adjustment period.

If my period totally stopped, I would try to regain more weight. It sounds like that’s what happened to you at 130 pounds and so you might consider that as a trigger weight to stay above. For me, I think it’s about 125.

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I think it’d be best to check with a doctor in case there’s anything that needs to be addressed, probably unrelated to IF.

I’ve been doing OMAD for a fairly long time, sometimes I fast well over 24 hrs and I don’t stop at any particular time of the month. My cycle hasn’t been affected. In my personal experience, fasting hasn’t affected my hormones. That said, I’m sure there’s plenty of women with different experiences, so I guess it depends on the body and if there’s any underlying condition.

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Thanks guys, I will visit a doctor if the bleeding persists after my period. As I have said above I’ve had mixed results before from weight loss and coincidental calorie restriction. I appreciate the responses and feel less alone, thank you.