My father too has MS, and is very bothered by heat and humidity, I have been told that barometric pressure is a real factor. I had never heard that meat and cheese could make it worse. My Dad has worstened to the point that he is in a nursing home, and is wheelchair bound, can do nothing for himself. It makes me a little angry because he refused to do anything to help himself, such as exersise of any type, and now can do nothing. I think you have to use it or you will loose it and he was told that by most of the doctors. He is very angry and expects much of his caregivers and family.
I don't think stress can cause it but many things including stress can
worsen the symptoms