I generally like Chinese food, and for all the years have not experienced acute hazards. But now a second time, after having dinner in a restaurant, I woke up in the middle of the night feeling like I have turned diabetic and having a headache and fast heart rate. Of course the immediate thought is the "Chinese Restaurant Syndrome" which is said to be connected to the use of Monosodium Glutamate (MSG) as a flavor enhancer. Even the chemical has been considered safe as a food additive and is in use for a long time, it has also been connected with causing brain damage and obesity. MSG is also used in fast food, but I guess people going to anything like McDonalds or Kentucky Fried Chicken (KFC) actually are suffering the brain damage already before they enter the restaurant. It might be just a "brain damage enhancer" then. And obese people are often very skillful blaming the fact that they eat too much on others, specially when they have enhanced brain damage at the same time.
MSG is also used in many convenience foods, where it has to be declared as ingredient (E621). Again, the last time I was eating something like convenience food, were Military Combat Rations in the 1980s. But also back then my exposure to MSG must have been low, because I usually traded out the main dish against the chocolate, cigarettes and condoms with fellow soldiers. These were accepted for payment of goods and services from our US allies and increased my wellbeing and social position in the barracks. Once, using this currency, I even bought a fully loaded Smith & Wesson Cal. 0.38 Revolver from an American soldier. Well, talking about brain damage: he must have had a lot of MSG.
Perhaps my low exposure, is why I am more sensitive to MSG. But it is also possible, that my current discomfort has nothing to do with MSG at all and it is just the oil used or ... who knows? It is always tempting in Beijing, just to pop in a restaurant. But of course there is not much control on the ingredients.