If there's anything wrong with MSG that isn't simply due to sodium intake, I think it's unknown to science (at least in the sense that there's no theory about it with any wide uptake). MSG is also intensively studied and has a very similar mechanistic story to aspartame.
One thing that is "wrong" with MSG is that a lot of restaurants overuse it as a condiment. So you're paying money for a good food experience, but you're getting the taste equivalent of instant ramen noodles.
I actually _like_ instant ramen noodles and MSG, and I use MSG when cooking. But it feels like cheating when fancy restaurants also use it.
> So you're paying money for a good food experience, but you're getting the taste equivalent of instant ramen noodles.
Restaurants, even nicer ones, cut corners. This especially flared up in the news a couple of years ago when a posh UK restaurant served a cheese plate at a decently high price, where the label was still on the cheese and revealed it had come from an ordinary supermarket’s house brand.
I’ve seen this personally, too. I ate sushi today at a sushi place where the menu said “crab sticks” were an ingredient of some rolls, but these were surely the imitation crab meat called surimi.
Or another Asian place in my area is known for offering “duck” on the menu, but what you get is mock duck[0] wrapped around the meat, to make people think it’s the duck skin, but the meat itself is chicken.
Sure, but it feels like a silly distinction. The famous example is water, which fits those same criteria. Would we that that there's not "nothing" wrong with water?