Which nation has the healthiest cuisine? ?

Japanese cuisine is considered the healthiest. They eat enough meat but don't overeat it like we Westerners do. And, as with most island-countries, they eat a lot of fish too. They also eat lots of vegetables with their stirfrys.

Nutritionists tell us that HALF of our plate should be vegetables.  Typical western meals are 0 to one-quarter vegetables (you can't really count potatoes or corn, since they are mostly just starch).

As for salad, iceberg lettuce - the lettuce that we buy most often - does not have much nutrition in it.  The most nutritious greens are kale, spinach, romaine/cos lettuce, and argula.

maybe mediterranean and japan

That would be a very debatable subject because what is considered unhealthy diet does NOT necessarily mean a nation that consumes it is a nation of unhealthy people.

Take for example, the 2 nations with the longest life expectancy - Japan, and France.  If you know anything about Japanese and French foods, you will know it is not healthy by western medical definition. We even have a name for this strange situation - the French paradox,

By the same token, what we think is a healthy diet does not translated into actual healthy people. Case and point, China. Many people think their diet is healthy, but China in  fact has a higher rate of heart disease than the US. And considering the US's rate is not good to begin with that only makes it worst.

If you want to live healthy, then you have to live a healthy LIFESTYLE.  Eating habits is only one aspect of health. For example, if you smoke, and don't exercise, , it is not going to matter how much healthy foods you eat.

A salad is a salad is a salad, and is served in every cuisine in the world. There is no one cuisine healthier than the others