This study aimed to determine the association between consumption of ultra-processed foods and obesity among Korean adults. We used the data of 7364 participants (men 3219, women 4145) aged 19-64 years from the Korea National Health and Nutrition Examination Survey (KNHANES), 2016-2018. Food items were classified using the NOVA food classification system, depending on the extent and purpose of food processing: (1) unprocessed or minimally processed foods, (2) processed culinary ingredients, (3) processed foods, and (4) ultra-processed foods. Consumption of ultra-processed foods accounted for 26.8% of the total energy intake. After adjusting for potential confounders including sociodemographic and lifestyle characteristics, subjects with the highest consumption of ultra-processed foods (fourth quartile of % energy intake from ultra-processed foods) had 0.61 kg/m2 higher body mass index (BMI; 95% confidence interval [CI] 0.23-0.99, p-trend 0.0047), 1.34 cm higher waist circumference (WC; 95% CI 0.35-2.34, p-trend 0.0146), 51% higher odds of being obese (BMI > 25 kg/m2; odds ratio [OR] 1.51, 95% CI 1.14-1.99, p-trend 0.0037), and 64% higher odds of abdominal obesity (men: WC ≥ 90 cm, women: WC ≥ 85 cm; OR 1.64, 95% CI 1.24-2.16, p-trend 0.0004) than those with the lowest consumption (first quartile) among women. However, no association was found in men. These findings provide evidence that high consumption of ultra-processed foods is positively associated with obesity in Korean women. Further studies with a large-scale cohort or intervention trial are needed to identify the mechanism of associations between consumption of ultra-processed foods and health-related outcomes including obesity in Korea.
Keywords: Korea National Health and Nutrition Examination Survey; abdominal obesity; obesity; ultra-processed foods.