I don't have stress because of the way I eat. I do however deal with a very hostile family on a daily basis. I'm talking, I get screamed and cussed out multiple times a day for things I had nothing to do with. One time I agreed with something my brother said and he came at me like a bull spittle flying every which way as he screamed at me, that ended with me Darth Vadering him until he was just about to pass out, which got him to shove me into my mom's 4 post bed, snapping an oak post off from shoving me so hard, which finally ended with me handing himt he post and screaming and drill-instructor shotuing a string of insults about his manhood at him telling him to be a man and club me with the post so I could defend myself and put his sorry arse out of it's miserable existence.
This is fairly routine kind of thigns at home, I've been forked by my mom before for helping her, because I wasn't helping her fast enough etc. I had to live with them (brother is 40, mother is 60 in a week) last year because I was going through bankruptcy, then health issues happened to my mom that still require me to live with her to help her out.
The way I deal with it, I ignore it, I flat out ignore them when they get irrational. The longer they go on I just start breathing deep and go about my business zoning them out. That's why I love going to the gym every day and walking, just walking, for an hour on the treadmill. It's me time, it's peaceful time. I put my hoodie over the TV screen on the treadmill, I put my headphones in and either listen to music or an audible book and just let my eyes unfocus and before I know it my hour is up and I feel great.
I suppose you could take a similar approach, tell them you love them and respect their opinions but this is something you want to try and if it ever clearly becomes a medical issue you will gladly stop and listen to their ideas. If that doesn't work, ignore them.