sandy, it's not that unusual for weight loss to become more difficult once you're nearer a lower weight but the types of exercise mentioned may not have helped in that sense with you. I've definitely noticed it and it was observed in tests in me that it was a contributing factor to my hormonal imbalance and I've heard HITT is counter to menopausal women as well. What is often overlooked is that most of these tests that seek out optimization of excercise are performed on either highly athletic or very obese men depending on the aim of the study. Optimal exercise and weight management is very much tied up with our hormones and men and women are very different in that regard. In men it's extremely hard to raise testosterone, and it's useful as it aids with muscle building, hence the steroid use, but it's terrible for a woman's cycle, never mind one with PCOS.
Another aspect in your experience may also be that you weren't eating enough to compensate for all the exercise you were doing, causing further stress to the body, shutting down into preserving what it has and making you reach a plateau. Did you calculate your BMR and TDEE according to new weight and exercise regime?
I tend to favour weight training or pilates these days. Works best for me, I occasionally do skip rope following the Tabata methodology which is a bit like HITT, that seems to be manageable (I can usually feel cortisol surges as they happen) being higher impact, and it's a pretty efficient way of exercising. I like it as it rids me of restless energy, which isn't good for
the body either. I don't push myself to the absolute limit though which was always stuck in my head as 'the proper way' to exercise. In my case it really isn't, HITT makes me gain, and it's not muscle, and drains my energy for days. The rest of it is incorporating low impact into your life, I cycle everywhere, take stairs where you can, long walks in the woods, etc.
It's worth reading up on cycle synching for the exercise component, the food aspects are less interesting to me as I'm more of the opinion that as someone with pcos those foods are all good any time of the month and I feel it's better just to have them when you feel like it (or they're in season even).
Apple, personally I'm very anti restriction of a specific food group, PCOS diets need to be sustainable long term not just for a short while. Broadly speaking moderate in complex carbohydrates (45-55% in terms of macros), high-ish in lean protein, go higher as you get older (25-35% macros), moderate in healthy fats (20-30% macros), definitely get the oily fish in twice a week. Fibre is important, get in 25g a day minimum. Cruciferous vegetables are really good for people with PCOS so they're usually a good starting point to build a meal around. The GI scale is a bit flawed but it is a good starting point for foods to eat rarely and often.
There are some concerns with regards to foods high in phytoestrogens like soy, flax seeds, sesame seeds, oats, etc. I personally do better without them in my diet but I do feel this is more likely anecdotal.
To tackle my testosterone levels a switch to exclusively organic dairy (always take it in full fat versions, reduced fat anything has more sugar, even the ones without added sugar, though there are some dairy products that are low fat naturally which is usually fine, like Skyr) made a good difference. I don't eat meat, but if I did I would have switched to organic exclusively there as they don't use hormones in rearing cattle, although this doesn't happen much in Europe, but there's plenty imported, so I mostly don't take any of it outside the house unless it explicitly states organic dairy is used, though a rare occasion won't trip me up, obviously.
The only thing I am exclusionary of is added sugar since it's all about insulin management and this just sets it off balance massively. Whole fruit is fine, juices and smoothies not so much. Obviously there are allowances for the odd bit of cake on a birthday worth celebrating or a fantastic pastry on holiday but it's really a rare thing and it better be fantastic when I do indulge. Reality is when you cut off sugar everything tends to taste far too sweet when you go back to it and hardly tastes like you remember, especially the mass produced stuff.
I've never been much of a drinker but stopped completely years ago. It makes blood sugar drop drastically and it's been theorised that the body can't metabolise fat for something like 24 hrs (more as you age).
I'm generally of the opinion that supplements are just expensive piss and if you Google PCOS and supplements you will get a list ridiculously long but with scientific backing there are a few worth taking.
Vitamin D, although the evidence surrounding it as the only medically backed supplement seems to be questioned at the moment, with PCOS there has definitely been shown to be a relationship that benefits from taking Vitamin D. My gynecologist recommends one 10,000iu of Vit S3 per five days but I find it hard to remember every five days so do 2,500 daily, makes my hair and nails grow really fast though.
There's also Myo inositol, 2g twice a day with a meal. Alpha lipoic acid (600mg) alongside it helps it perform even better. Gynecologists will often push a Myo and Ciro inositol combination product with women TTC. It's expensive and the research indicating the need for a combination approach with a specific ratio is based on one small case study, but it was specific to women with PCOS whereas the 2g Myo was performed on those with insulin resistance. Anyhow, inositol is considered a good supplement to use to help keep glucose levels steady.
Only other supplement I'd consider is an Omega 3 if you don't/can't get oily fish in often enough.
Apologies for the length 