Though I'm using a picture which talks about "health", I'm pretty sure that the lack of sugar bombs in most Japanese food has less to do with health and more to do with tastes based on food culture.
Each country has its particular cuisine and preferences, and America loves its sugar. This is not a genetic defect or some sort of lack of restraint in the face of an option to choose sweets. It's a preference formed from years of experience with the same types of food. If you give people very sweet food all of their lives, they will have a taste for it. One of the things I've encountered much to my dismay in America is that sweet things are often intensely sweet. In fact, they are sometimes so overbearingly so that I can't taste much of anything else. The flavor depth is obliterated by sweetness.
In Japan, it was rare for things to be so intensely sweet that you couldn't taste anything else. Sometimes, things didn't have enough sugar, and that was an issue, but I grew used to having more flavor depth and I miss the lower sugar content of Japanese sweets.