But you don’t know how much MSG is in the food you eat. You base it on whether you have a reaction. If you have a reaction, you believe MSG is the cause.
Not exactly scientific.
Allergist will have a patient keep a food diary. If you have the same reaction after eating the same thing and it happens over and over, you know you are having an allergic reaction and it is relatively easy to figure out what is causing it.
Some reactions happen within 20 minutes but others don’t happen until the food is digested. It took me a while to figure out that the migraine type headache that I woke up with at 4am, was caused by the chocolate that I had eaten for dessert. I loved chocolate and I didn’t want to believe it.
I haven’t eaten chocolate in years.