Why can't Japan eat while walking?

Is this a custom? They think it is impolite to eat while walking.

The default habit of Japanese is not to walk and eat in crowded places, which they think will make others feel uncomfortable. For example, in subways, urban areas and buses, you won't see Japanese eating there.

In order to "buy time", especially in the morning, some people often eat while walking, thinking that this will not only save time, not delay work, but also eat breakfast, which is killing two birds with one stone, but it is a bad habit that does not pay attention to hygiene and is harmful to health. This is because: (1) people come and go on the road, the dust is flying, and cars emit a lot of harmful substances, all of which float in the low altitude. When you eat on the roadside, you will inevitably take in a lot of harmful substances with the food;

The digestion and absorption of food should be completed under the unified command of the brain. While walking and eating, the brain should not only command the motor system, but also the digestive system. It is not only difficult to digest the food eaten well, but also easy to choke, bite the tongue and cause foreign bodies in the trachea. Therefore, it is not advisable to eat while walking.

Most Japanese people don't have the habit of eating while walking, such as standing on the balcony or vending machines. It can only be said that there is no such habit in their behavior pattern, and the Japanese usually only focus on one thing.