[deeviant]

The Mindspan Diet, by Preston Estep has a lot to say about the Japanese diet. I think he makes many convincing arguments. Some key take-aways: Iron is very bad for longevity, refined carbs that aren't sugar and that have relatively low glycemic indexes (long grained rice and many pastas) are actually quite good (rice/pasta), meat bad but seafood ok, don't over do the saturated fat in general, drink moderate alcohol if at all.

I got a lot from How Not to Diet. I also got a lot from the Mindspan diet. I think the truth is out there, but as you have already put it, it's pretty bloody hard to get anything definitive. It's hard because it takes decades to prove anything and it's hard because food is big business and entrenched food production pipelines protect themselves against disruption the best they can (looking at you, sugar industry).

[saiya-jin]

Seafood specifically can't be judged as some ideal one 200 years ago prior to oceans pollution. If you want to pick up seafood which is not heavily contaminated by heavy metals, various regional spills, factory drains, near deltas of biggest rivers in Asia/Africa etc. you will find out you just play russian roulette with your food. Mercury poisoning with ie tuna can be achieved relatively quickly depending on the brand. Pregnant women should probably avoid things like salmon & tuna completely, the benefits are far outweighted by the crap. Farmed sea fish are properly bad food.

Freshwater fish can be better but they are almost 100% farmed, and good luck trusting some farmer with what he feeds them, since infections in overpopulated ponds are very frequent. Fish meat reflects what its being fed, so crappy food makes previously healthy fish into more bacon one.

Also meat is not an uniform substance, cheap beef is most probably less healthy than lean bio free range turkey. Also depends on the cuts, pork has very lean and very fatty tissues in the same animal. And so on.

I'd say for the food the quantity, timing, being active every day for longer stretch, calm peaceful life and obviously not much poisons/addictions makes up more than rest. We have centenarians in the west too. At least that's the best effort, if one has crappy genes with high probability of cancer or heart attack before 50, there are sadly some limits these days. But one can and should still maximize their own potential.

[deeviant]

I'm mostly a vegetarian except that I do take molecularly distilled fish oil. Very simple way to get some of the health benefits of seafood consumption but take no risk.

However, I actually feel mercury isn't nearly the bugaboo that vegan proponents often make it out to be. High ocean mercury levels have been a thing for over 100 years. Yet a great many studies have found seafood to be beneficial to longevity and overall health.

All of your points sound like vegan talking points, but to each their own.