From Washingon Post:
As women in the United States and across the industrialized world get fatter, most Japanese women are getting skinnier. Still, many view themselves as overweight. The trend is most pronounced among women in their 20s. A quarter-century ago, they were twice as likely to be thin as overweight; now they are four times more likely to be thin.
Social pressure — women looking critically at other women — is the most important reason female skinniness is ascendant in Japan. “Japanese women are outstandingly tense and critical of each other,” said researcher Hisako Watanabe, who has spent 34 years treating women with eating disorders. “There is a pervasive habit among women to monitor each other with a serious sharp eye to see what kind of slimness they have.”
Public health experts say that younger Japanese women, as a group, have probably become too skinny for their own good. Restricted calorie consumption is slowing down their metabolisms, the average birth weight of their babies is declining, and their risk of death in case of serious illness is rising.
“I would advise these women to eat when they are hungry,” said Satoshi Sasaki, a professor of preventive epidemiology at the University of Tokyo School of Public Health. “They should be satisfied with a normal body.”