Japanense usually don’t peal apples. That’s because there has been too little information about food in Japan for years. While Europe and the US already knew the positive effects about apple peel (such as the deprivation of antioxidants, potassium, calcium, vitamin C and other Fiber) those facts were still unknown in Japan.
However, studies show that it there is a clear trend in an upward direction. More and more Japanese are enlightened and learn about the positive effects of apple peel.
Pesticides, a reason for many japanese
However, many Japanese also believe that the peels are filled with pesticide or other chemicals, and therefore would clearly be harmful to health.
Other reasons for this are the rainy season in Japan, which is different than in Europe or North America, because it provides for harder layers of apples, and thus are inedible for many Japanese. Others just like to eat it without the peel.
Simply put, because some Japanese have health concerns, they taste better that way or were taught by their parents to do so.
It is by no means a tradition in Japan to peel all fruit.