Have you always been very slim? I'm wondering because I have some friends who have been slim their entire adult lives. As they approach menopause they have gained some weight, which isn't a lot but it is new for them and therefore disconcerting. They have maintained with IF but it's definitely not as effortless for them as it once was. Just a thought..
Ironically, as I'm approaching (possibly in) menopause with IF, I have stayed relatively slim for the first time consistently in my adult life, but it's all relative :) I still have a bit of flab here and there, esp. my thighs, but to me it is still a huge success (I'm now a Boden 4P, down from 10P) as I can maintain this pretty easily and like the lifestyle so it's sustainable.
Could it partly be due to bloating? That is an issue for me and always has been, thought it's not as bad as before. I wonder if upping your water intake might help?
Can you ask a question on the FB page? The moderators are usually good at brainstorming, but I haven't been on it for a long time. I think they would say stop weighing and focus on how your clothes fit and how you feel. Some people say if they close with XYZ food they do better, but I don't remember exactly what. I haven't looked into this, but if you are motivated you could:
https://dddsocialnetwork.com