I’ve done a 7 day fast leading up to my period and I seem to always start 3 day fasts leading up to my period. I don’t find it any more challenging and 3 day fasts are a breeze for me. If I’m not doing a long fast when I have pms, I’ll tend to eat a lot more. But I’m not trying to lose weight and I just listen to my body. I do think I tend to start 3 day fasts before my period due to the feeling of bloat. Just an instinctual feeling that I don’t feel good and a fast would help.
Glad you brought this up because I was going strong on IF for 3 weeks and then the day my period hit (overnight) when I woke up in the morning I could not make it past 9am (I start eating at 12pm usually). I felt nauseous and on the verge of vomiting so I ate and felt better right away. Same the next day. So I’m thinking things shifted a bit with the period hormones. But now I’m back to the usual after 2 days of that.