In recent decades, Japanese people's dietary fiber intake has been decreasing. Compared to 1947, dietary fiber intake in 2008 had decreased by roughly half.

The breakdown for dietary fiber intake makes it clear that the percentage of grains in particular has decreased over time. This decline has been caused by an increase in the intake of meat and dairy products that have accompanied the Westernization of eating habits in Japan. The intake of rice has decreased and people have stopped eating grains such as barley.