The Breast Illusion

Last time I lived in Tokyo I was fat but tall, I think I have mentioned this before. However, I was the same height as now, and might even have been a few kilos less. Now I see fat Japanese girls all over town, everyday, and I still feel tall but average size wise. I even fitted an M-size shirt I bought the other week. It was a bit tight over the chest though, otherwise good.

And this is what really puzzles me, breast size. Mine seem to have got bigger, or have I become smaller and they stayed the same? Do they swell in the heat? Or is it all an illusion, me feeling thinner but being the same, still comparing myself to the most often small chested Japanese girls?