The Cost of Being Thin: South Korea's Pursuit of Slimness and Its Health Consequences

In South Korea, K-pop star Jang Won-young of the group Ive is widely admired for her slender look. At 173 centimeters tall and weighing 48 kilograms, her estimated body mass index of 16 is well below what is considered healthy, highlighting a broader trend affecting many women in the country.

According to data from the Korea Disease Control and Prevention Agency released on Wednesday by lawmaker Heo Jong-sik of the ruling Democratic Party of Korea, 6.2 percent of South Korean women were underweight in 2025, defined as having a BMI of 18.5 or lower. That is almost four times the rate for men, at 1.6 percent, and above the national average of 4.2 percent.

The share of underweight women exceeded that of men in every region, with the highest rate recorded in Seoul at 8.2 percent. By contrast, obesity was more common among men nationwide, reaching as high as 49 percent on Jeju Island. On average, 41.5 percent of men were classified as obese compared to 24.2 percent of women. In South Korea, obesity is defined as a BMI of 25 or higher, a lower threshold than the global standard of 30.

Pressure to be thin and distorted body image

Heo said that while preventing and managing obesity remains important, society should examine whether expectations for women to be thin are driving unhealthy weight loss. He expressed concern about the growing use of weight-loss drugs in Korea and called for stronger regulation to prevent people with a normal or underweight BMI from using them.

Studies show many Korean women misjudge their own weight. An August report from the Korean Society for the Study of Obesity, based on the KDCA's annual national survey from 2022 to 2024, found that 18.9 percent of women with a normal BMI between 18.5 and 24.9 considered themselves obese, compared with only 4.1 percent of men in the same weight range. Even among underweight women, 0.6 percent believed they were obese.

A separate KDCA analysis published in 2024, covering the period from 2013 to 2021, found that 15.1 percent of women aged 19 to 29 were underweight. Among them, 16.2 percent said they had tried to lose weight. More than half of women with a normal BMI, 53.9 percent, also reported attempting to lose weight.

The report warned that a social and cultural preference for very slim bodies is encouraging excessive body consciousness and extreme dieting among young women, which can have serious health consequences.

Health risks of being underweight

South Korea is not among the most overweight nations. It has the second-lowest obesity rate in the Organisation for Economic Co-operation and Development after Japan. Under Korea's definition, which corresponds to overweight in many other countries, the share of overweight Koreans is still lower than the share of obese people in the United States, according to the OECD's latest data.

The data also show that obesity among women has not risen significantly. Between 2015 and 2024, the male obesity rate jumped by nearly 10 percentage points, while the rate for women increased by just 0.3 percent.

Experts note that falling below a healthy weight range can deprive the body of essential nutrients. Being underweight has been linked to a weakened immune system, higher risk of osteoporosis and anemia, and delayed growth in children.

A nationwide cohort study published in 2022 in Scientific Reports found a clear link between low BMI and fractures. Koreans who were severely underweight, with a BMI below 16.5, had a 28 percent higher risk of fracture than those of normal weight. Those who were moderately underweight, with a BMI of 16.5 to 17.4, had a 14 percent higher risk, while those who were mildly underweight, with a BMI of 17.5 to 18.4, had a 9 percent higher risk.