The problem will always be that you need to find places that keep good records, and have done so for the last century.
What they set out to do was to find correlations between lifestyle and longevity, and what they ended up finding was a great tool for spotting pension fraud.
The glass of wine recommendation has had many studies done and the results are conflicting.
The eating guidelines like heavy in plants, mederteranian, eating to 80% full all have multiple studies showing benefits over the typical western diet and especially the typical American diet. It's a no brainer that if you want to live a long life you have a better chance of doing that if you have a reduced risk of heart attack, stroke, diabetes, etc.
There are also many studies that suggest other kinds of diets are beneficial, and many populations that consume significantly different diets and have even better health than the average person around the Mediterranean. For example, inuit populations also display generally low obesity and risks of heart attack, stroke, diabetes etc - while consuming almost the opposite of a Mediterranean diet or of plant heavy diets.
That doesn't seem to be true.
https://pubmed.ncbi.nlm.nih.gov/30578133/
The studies backing up specific diets are not population level, but rather specific study groups. And yes, there are other healthy diets too.
I mean, that’s not nothing, y’know?