3 days ago
Female Underweight/Undernutrition Syndrome to be classified disorder
The Japan Society for the Study of Obesity announced in April that it will recognize a new health disorder affecting women, to be classified as Female Underweight/Undernutrition Syndrome, or FUS, linked to being underweight and suffering undernutrition.
According to the group, known as JASSO, 20% of women in their 20s in Japan are underweight, one of the highest rates among developed countries. It plans to establish diagnostic criteria for the syndrome as part of efforts to promote early detection and prevention.
The trend toward thinness among young women in Japan has become increasingly pronounced in recent years.
According to the health ministry's 2023 National Health and Nutrition Survey, 12.0% of women aged 20 and over were classified as underweight on the basis of their body mass index, or BMI, a standard measure used to assess weight status. By contrast, only 4.4% of men in the same age group were considered underweight. By age group, 24.4% of women in their 20s and 17.9% of women in their 30s were underweight.
The calculation of BMI involves dividing people's weight in kilograms by the square of their height measured in meters. According to JASSO guidelines, a BMI of 22 is considered the standard, with a reading below 18.5 classified as "thin" or "underweight," between 18.5 and below 25 as "normal weight," and 25 and above as "obese."
JASSO defines FUS as a condition in which extreme weight loss and undernutrition in women age from 18 up to menopause leads to a range of health issues. These include decreased bone density or osteoporosis, irregular menstrual cycles, muscle weakness, anemia, fatigue, depression and metabolic abnormalities.
FUS can lower quality of life over the medium to long term and increase the risk of frailty, declines in mental and physical vitality and other aspects of life often associated with aging, according to the society.
Explaining a major factor contributing to the rise of FUS, the society noted that "the value equating thinness with beauty has become widespread, leading many, especially young women, to engage in weight-loss behaviors such as restricting food intake."
In 2023, My Well Body Kyogikai, a group dedicated to women's health issues, conducted an online survey of 1,000 women in Japan between the ages of 16 and 23. The results revealed that about 20% of underweight women, and more than half of women with a normal weight, considered themselves to be "fat."
Additionally, 16% of underweight women and 48% of women with a normal weight said they wanted to lose more weight. The most common motivation cited was the desire to feel more confident about themselves.
The survey results also suggest that social media platforms such as Instagram, YouTube and TikTok may be influencing a range of weight loss behaviors.
In recent years, the use of medications originally developed for the treatment of obesity and diabetes has surged among individuals seeking to lose weight, a trend that has raised concerns among health experts.
Such drugs typically work by suppressing appetite or increasing the excretion of sugar through urine, leading to weight loss as a secondary effect. There are worries about health risks, however, including acute pancreatitis and other serious side effects.
Wataru Ogawa, executive director of JASSO, said, "Medical systems and public health measures (in Japan) have historically focused on combating obesity, while systematic approaches to address underweight and undernutrition have been insufficient."
He emphasized that the organization plans to establish diagnostic criteria and promote educational initiatives, following the collection of relevant medical evidence.
