I'm sure MSG was something I regularly consumed on previous SAD diet without noticeable effects. A couple months ago (after being paleo for 8 weeks) i went to a chinese buffet and had some shrimp and sauce - after we left I had mild symptoms - felt like my heart was racing and my chest was tight. Came home and did some research and found that it was probably MSG sensitivity.
Fast forward today when I was desperate for something to eat and found some salmon burgers (with salsa, sour cream and 2 squares of Lindt 85%) that I had purchased at Sam's when we first started paleo because they were "healthy" - about hour after eating I'm sitting on couch and talking on phone and the room starts spinning and I'm having trouble talking - silly me thinking it's my imagination, just need to get some fresh air - i go out to the store and end up pulling off the road because I feel like I'm driving drunk. Nauseous,..spinning, heart feels like its racing, hard to breath,...end up having to go home a sleep it off. It was bad, real bad,..I don't want to ever feel like that again. A really bad strange drunk.
Get around to reading box and find autolyzed yeast extract as an ingredient - searching around seems to link it with MSG.
Have you become extra sensitive to MSG since going Paleo?