The emphasis on fresh high-quality food made me wonder if that sort of food is more satisfying (and filling) than what the author sees in American food. Does eating poor quality food leave you hungry? (Also, consider people living in “grocery deserts” who subsist on large amounts of fast food. Their obesity rates are very high.)
One thing that the article barely touches on, but is another huge factor, is price. You can get an excellent meal in Japan quite cheaply. Meanwhile, food in the US (and especially anything you get from a restaurant) is expensive.