this says it's 7% in Japan: https://worldpopulationreview.com/country-rankings/diabetes-... , but I found another source that says 12% for 2016.

Diabetes scales with obesity and age. Japan has a very old population, but less obesity than the US. White rice despite its glycemic index is not super high calorie. If it's a contributing favor, it's because of weight-gain, not glycemic index.

edit: better source: https://www.diabetesatlas.org/data/en/country/101/jp.html, https://www.diabetesatlas.org/data/en/country/211/us.html

There's more diabetes in the US.