Just saw this article on the Japanese living so long. It says, first, that it isn't about the diet, but there's a lot of stress, which would make such long life less likely.
Or maybe it is the diet, but that's unproven.
Then we delve into the diet a little bit (it's a short article), and then we hear that that can't possibly be all of the explanation.
And then there's a whole lot of nothing; kind of a mental "throwing things at the wall".
Of course, they don't even mention one other likely contributor: the fact that all elderly Japanese have access to healthcare.
I really don't know what the answer is; I suspect that both food and healthcare are significant contributors, and I suspect that there's some workplace stress-related contributors. To whit, there's a lot of emphasis put on showing up for work in Japan, even when sick, but little to no emphasis on getting things done. There's also mention of how many hours Japanese work, but no recognition that Americans work the most hours in the world. But this article is just an incoherent mess without any central message.