Sorry I didn't answer you yesterday Lost; I was at work then physio, then collapsing and sleeping...!
You asked about joint hypermobility syndrome (JHS)... It is badly diagnosed: apparently 50% of people with it have it for ten years or more before diagnosis. That probably includes me, but to be fair my symptoms have only been really bad for 2 years or so.
It is diagnosed with something called the Brighton criteria. The major dx factors are bendiness in 4+ of 9 key joints, plus pain. There are minor dx factors too, including presence of varicose veins and hernia.
There's more info here in a DWP doc written by the UK's JHS 'expert'.
I am only just coming to terms with it, and haven't yet got on top of managing it... But I definitely think stress exacerbated my symptoms. Then trying to avoid pain made me exercise less, and I have put on about 15-20kg, which also puts much more stress on my lower joints. I haven't noticed any food effects, but I have been veggie since 1987 anyway. I suspect hydration also plays a role: I am constantly thirsty (and diabetes has been ruled out) and I think my pain is worse if I don't drink enough water. I need to exercise too - I know it helps and the muscles around my joints need to be stronger to compensate for the loose connective tissues - but the right balance is hard to achieve because it hurts.
I self-referred to a health trainer via our local social care system, before formal diagnosis. She had RA and was helpful and inspiring. She emphasised being kind to yourself, eating well/whole foods, exercise and 'mindfulness' techniques. (Our local pain clinic uses mindfulness too, but I can't get a referral). She has had RA for 20 years and had had visible surgery on her fingers, but has pain free days following her own recommendations. :)
BTW Lost, my dad had a dx of RA, but the rheumy said it was prob actually JHS misdiagnosed... So it's def worth exploring.