Is Being Thin Worth the Risk? South Korea's Weight-Loss Culture and Its Hidden Health Dangers

Seoul — Jang Won-young, a member of K-pop group IVE, stands 173 centimeters tall and weighs just 48 kilograms. Her slender frame is widely celebrated across South Korea, but her body mass index of roughly 16 signals potential health risks associated with being significantly underweight — a problem shared by many women in the country.

New government data underscores the scale of the issue. According to figures released Wednesday by lawmaker Heo Jong-sik of the ruling Democratic Party of Korea, drawing on statistics from the Korea Disease Control and Prevention Agency, 6.2 percent of South Korean women were classified as underweight in 2025. That is nearly four times the 1.6 percent recorded among men and well above the national average of 4.2 percent.

Regional Patterns and the Gender Gap

The underweight rate among women exceeded that of men in every region of the country, reaching its highest point at 8.2 percent in Seoul. Meanwhile, obesity was far more prevalent among men, with Jeju Island recording the highest male obesity rate at 49 percent.

Nationally, the average obesity rate stood at 41.5 percent for men and 24.2 percent for women. Notably, South Korea uses a BMI threshold of 25 to define obesity, which is lower than the international standard of 30.

Heo highlighted the cultural dimension of the problem. "Preventing and managing obesity is important, but we also have to examine whether societal pressure on women to be thin is driving weight loss that harms their health," he said. He expressed particular concern over the growing popularity of weight-loss medications in Korea, calling on authorities to tighten regulations and bar individuals with normal or underweight BMI from using such drugs.

Many Normal-Weight Women Believe They Are Overweight

Research reveals a striking disconnect between reality and perception. An August report by the Korean Society for the Study of Obesity found that 18.9 percent of women with a BMI in the normal range — between 18.5 and 24.9 — considered themselves obese. Among men of normal weight, only 4.1 percent held that view. Even 0.6 percent of underweight women believed they were overweight, according to an analysis of nationwide survey data collected between 2022 and 2024.

A separate KDCA analysis covering the years 2013 to 2021 found that 15.1 percent of women aged 19 to 29 were underweight, and of those, 16.2 percent had attempted to lose even more weight. Among women with a normal BMI, a striking 53.9 percent tried to slim down.

The report warned that a cultural emphasis on thinness and reckless dieting is fueling unhealthy body image among young women, and that unnecessary weight loss can trigger serious medical consequences.

A Lean Country Where Men, Not Women, Face the Obesity Problem

South Korea is not a particularly overweight nation. Its obesity rate ranks second-lowest in the Organization for Economic Cooperation and Development, behind only Japan. Because Korea's obesity cutoff is lower than the OECD standard, the share of overweight Koreans is actually smaller than the share of obese Americans, according to the most recent OECD data.

And contrary to the self-perception of many Korean women, the female obesity issue is far less severe than the male one. KDCA data shows that the male obesity rate climbed by nearly 10 percentage points between 2015 and 2024, while the female rate barely budged, increasing by just 0.3 percentage points over the same period.

The Health Costs of Being Too Thin

Being underweight means the body may not be receiving adequate nutrition, with consequences that can range from weakened immunity and increased risk of osteoporosis and anemia to growth delays in children.

A 2022 nationwide cohort study by Korean researchers quantified one such risk. Published in Scientific Reports under the title "Severity of underweight and risk of fracture: a Korean nationwide population-based cohort study," it found that severely underweight Koreans with a BMI below 16.5 had a 28 percent higher fracture risk than those at normal weight. Even moderately underweight individuals (BMI 16.5 to 17.4) faced a 14 percent increased risk, while those who were mildly underweight (BMI 17.5 to 18.4) saw a 9 percent rise in fracture risk.