Processing is defined in the legislation. By and large it's ingredients most people use and recognise in their own kitchens. Fancy means something that doesn't fulfill that definition.
The point of anti UPF sentiment isn't to be healthy per se, but to remove the disconnect between food as most people understand it and we evolved to handle and what is typically produced in industrial kitchens.
The idea that we can process our way to a healthy diet has not stood up to the real world experimentation. Maybe it's time to stop experimenting on school children and just accept that perhaps they should be fed food that is generally recognised as such down to its base ingredients.
We really are not in a good position to assert what foods are "healthy" and which are not. Many long held views on things like saturated fat simply don't hold up when you view the ingredients in isolation. Research on health factors related to food is incredibly difficult to do.
That said, we can look at proxies like "what do healthy people tend to eat more of?", and the clear evidence is that people that are healthy by and large have diets that are low in UPFs and high in home prepared food. Of course, this could be a correlation, but until we have this properly established, the precautionary principle would be that we shouldn't eat too much in the way of UPFs, because that necessarily also implies food prepared and cooked in a way we know to be correlated with health. We certainly shouldn't be pushing it on our children.
There's no circularity. You asked me what processing meant and I said what it says in the legislation, which is pretty similar to the Nova classification. That definition was used because it's broadly useful without being overly restrictive.
By all means use MSG - nobody is stopping you. But there's a good hypothesis that MSG is problematic precisely because it is one thread of hyper-palatable food. Of course soy sauce or miso contain plenty of MSG (or at least a close analogue), but they also tend to influence flavour so are hard to use to excess; they also cost more so there's an cost pressure to limit excessive use.
The point of anti UPF sentiment isn't to be healthy per se, but to remove the disconnect between food as most people understand it and we evolved to handle and what is typically produced in industrial kitchens.
The idea that we can process our way to a healthy diet has not stood up to the real world experimentation. Maybe it's time to stop experimenting on school children and just accept that perhaps they should be fed food that is generally recognised as such down to its base ingredients.