I had a total hysterectemy at 39, I kept one ovary ( the doctor "cleaned" it up for me, I had horrible endometreosis and had surgery before for it. We wanted another child, but it didn't happen. I have one beautiful daughter though) I never took the HRT, I am now 56, so the combo of Thyroid and post meno is tough. I had shoulder surger 6 months ago and knee surgery in december, so the slower activity has also been a factor, but I am ramping that up now.
I know the body goes into starvation, by background is BioChemistry, so yes it does happen. The biggest thing with IP is that I personally think we should have a bit more "fat" like avocado or other healthy fats. We need fat to process other foods and our skin (esp my age) needs it, it is also very good for your hair & it helps us absorb vitamins. So, I (not toting that others should) am thinking in 2 more weeks (if losses are super low) adding some more "good" fat, like maybe 1/4 of an Avocado per day and see if that helps. I have to prescription Vit D because mine is so low and so was B12, although my B12 was normal in december after supplementing. I am also doing gluten-free since the first of the year. I am not super strict, but on this diet there is very little gluten. My doctor and I are seeing if that will help my Vit D levels, she thinks I am not absorbing and that can be a gluten problem. Hence, adding in a little more fat may help also. Sorry for the long post.