I don't think the GP is talking about a centuries old diet (note the use of tense e.g 'in modern china, most food
is).
Sure, the vestiges of that diet still exist today as do many of the cultural beliefs and habits e.g. only eating cooked foods unless they have a thick, peelable skin, boiling water before drinking it etc.
The point I am trying to make is that the Chinese have taken that traditional diet and added a huge amount of sugar, salt and MSG, not to mention significantly more meat (in recent years, this can often be doctored with water and/or various chemicals by the vendor). If you're eating at a restaurant rather than at home, meals probably contain a good dose of gutter oil too.
That should not be taken in any way as being healthy, and because it's also relatively recent, the effect it will have on the health population is not yet highly visible.
In mainland China they also have a poor concept of proper nutrition and this is exacerbated by the one child policy, with parents and grandparents feeding their only child whatever they want to eat (often sweets, candy, soft drink) rather than what is good for them.
On multiple occasions in China I've known children under the age of 5 with rotting, horrible teeth and when I brought it up with the parents and/or relatives (who I also knew) they laughed it off and said "oh it doesn't matter, they're just baby teeth and new ones will grown in soon and they'll be ok".
They completely failed to realise they were setting their children up for a lifetime of diet, teeth and health related problems.
I've got no problems with the concepts of traditional Chinese cooking, but it's increasingly difficult to find that in modern China.