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South Korea Obesity Rate 2025: What the KNHANES Results Show

ByLife Choice Note

In brief: South Korea’s 2025 Korea National Health and Nutrition Examination Survey (KNHANES) estimated obesity prevalence at 49.1% among adult men and 28.7% among adult women. The estimate reached 59.0% among men in their 30s. These are provisional population statistics, not an individual diagnosis, and the survey defines obesity as a body mass index (BMI) of at least 25 kg/m².

What does the 59.0% figure measure?

The Korea Disease Control and Prevention Agency (KDCA) released the provisional 2025 KNHANES results on 30 September 2026. Overall male obesity prevalence was 49.1%, only 0.3 percentage points above 2024. The age breakdown was less uniform: prevalence among men aged 30–39 rose from 49.1% to 59.0%, while the figure for men aged 50–59 rose from 48.1% to 54.0%. Among men aged 40–49, prevalence was 53.3%, down 8.4 percentage points from the previous year.

Among adult women, obesity prevalence was 28.7%, up 2.5 percentage points. The estimates were 28.3% for women aged 30–39 and 31.6% for women aged 40–49, increases of 3.7 and 5.9 percentage points respectively. The age-specific movement matters: a headline saying that obesity surged in every group would misstate the data.

What changed in physical activity and chronic disease indicators?

The share of adults meeting the survey’s aerobic physical activity definition fell to 49.5%. The year-over-year decline was 11.2 percentage points among men in their 20s, 7.6 points among women in their 20s and 8.3 points among women in their 30s. Strength-training participation was 26.4%, and walking participation was 41.7%; both also edged down from 2024.

For adult men, hypertension prevalence was 28.2% and high-cholesterol prevalence was 26.1%, increases of 1.9 and 2.7 percentage points. Among men in their 50s, diabetes, hypertension and high-cholesterol prevalence rose by 7.7, 5.4 and 9.4 percentage points respectively. These outcomes use different definitions and measurement rules, so the percentages should not be added together or treated as one person’s combined risk.

Does the survey explain why obesity changed?

No. KNHANES can show that several population indicators moved at the same time, but this release does not establish that one caused another. In 2025, fat supplied more than 30% of energy intake among adults in their 20s and 30s. Average fruit intake fell from 169.0 g in 2016 to 107.7 g in 2025, while beverage intake increased over the same decade. Those patterns are useful for public-health planning, but they cannot identify the cause of an individual’s weight change.

Three limits to keep in view

  • The 2025 estimates are provisional. KDCA says the detailed statistical report and public-use data are due in December 2026.
  • Not every figure is processed the same way. Year-to-year national comparisons are age-standardized to Korea’s 2005 projected population, while age-group estimates are crude rates.
  • This is a sample survey, not a personal scorecard. KNHANES covered about 10,000 people from 4,800 households in 192 areas, using examinations, interviews and self-administered questionnaires. Sampling variation and self-report error remain possible.

Definition is another major issue. KNHANES classifies obesity at BMI ≥25 kg/m². Many international datasets use BMI ≥30 kg/m² for “obesity.” Comparisons across countries can therefore be misleading unless the BMI threshold, age range and standardization method match.

How can an individual use the information?

Population data can suggest what to track, but they do not tell a reader that they personally have a disease. The BMI calculator can organize height and weight, while the blood pressure, pulse pressure and MAP calculator and the LDL and non-HDL calculator can help record measurements. Calculator outputs are not diagnoses; repeated measurements, medicines and symptoms need clinical context.

Primary sources and review

Sources reviewed 1 October 2026. Scope: provisional 2025 KNHANES results for South Korea. Prepared by Life Choice Note. This independent health-information commentary does not diagnose obesity, hypertension or diabetes and does not provide individual treatment instructions. Sources and corrections policy.

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