The country that eats the least spicy food is Japan.
Japan is a country that eats relatively mild or less spicy food when compared to other parts of the world.
The reason why Japan eats relatively mild or less spicy food when compared to other parts of the world is due to culinary history and cultural preferences.
Japan focuses on highlighting the natural flavors of fresh ingredients in their foods.
Japanese cuisine traditionally emphasizes the delicate flavors of fresh, high quality ingredients, instead of relying on strong spices for the flavor of their food.
And as an island nation that has a long history of also relying on seafood, Japanese food culture also evolved to appreciate the subtle tastes of the sea.
Although it's not the only factor, the climate of Japan, is also not one that is known for producing extremely spicy peppers, which can also contribute to the preference for milder flavored foods.
Japanese people also tend to have a lower tolerance for strong smells, which can also be associated with some spicy ingredients, which also further influences their culinary choices.
However some regional dishes in Japan do use some spice, although the spices used are often less spicy than other spices and there are also some regional variations in spice levels.