For quite some time now, Japanese women's breasts have, on average, been getting larger. And it's not just so-called "AV idols" like Yoko Matsugane, Harumi Nemoto, Rio Natsume, Kazusa Sato, or Eiko Koike. (You have no idea how long it took me to research all those names, none of which I knew before writing this post. Really.) It's a nationwide phenomenon.

Via Gaming Age Forums, Japan blogger "santos26" reports that the mix of bras sold by Japanese lingerie maker Wacoal has steadily shifted towards larger sizes since at least 1980:

According to this research, in 1980, 58.6 percent of bra they sold were A-cup ones, and they did not have to produce bra over E-cup. However, in 1992, the ratio of A-cup girls become 25.9 percent of all, and in 2004, it finally became around 10 percent of all girls. On the other hand, the demand for larger bra increased, and now 12.7 percent of girls are using bra over E-cup. Amazingly, In other words, 12.7 percent of Japanese girls are kyonyu (the owner of big boobs).

Western readers should bear in mind that Japanese cup sizes run differently; a Japanese E is roughly the same as an American D. But the trend is impressive nonetheless. So what's causing it? Santos26 offers a hypothesis: "Maybe it is thanks to junk foods which include a lot of fat."

That might indeed be the case. The Mainichi Shimbun reports that young Japanese women are abandoning the famously healthful Japanese diet of yore in favor of junk food that's often been super-sized beyond all reason. For example, there's the massive Tokudai Soft Cream, an ice cream cone over a foot and a half high. A woman who tried it says:

"I found the Tokudai Soft Cream at Daily Chico in (Tokyo's) Nakano... It probably weighs more than a kilogram. And it only costs 300 yen! There is one problem with the super-sized ice-cream and that's trying to eat it all before it melts."

So far, so good... but there's a darker side to the trend. Japan's increasing junk food consumption is starting to boost obesity rates among the younger generation. As the Mainichi reports:

Only 24 percent of Japanese aged 15 and older are believed to be overweight, compared to about 65 percent of adults in the United States.

But concern is growing... Instead of the fish, rice and miso soup of their grandparents' generation, younger Japanese are increasingly wolfing down fast food like burgers, fried chicken and instant noodles.

Bad diet and less exercise create what psychologists say is a vicious cycle: Fat kids are increasingly picked on at school, get depressed and find solace in eating even more.

Perhaps, then, Japan is in the midst of a brief but wonderful golden age, with its women getting just enough fat in their diet to develop fully, but not quite so much that they become obese. Enjoy it while it lasts, guys.

And for the ladies, sorry, but life isn't fair. A fatty diet doesn't help men look any sexier. As Tokyo Times reports, it just makes us need man girdles.