There is growing evidence for a global transition to a more highly processed diet. While the dietary share of ultra-processed foods depends on a country’s economic status, food choice and consumption are also influenced by the socioeconomic situation of individuals. This study investigated whether ultra-processed food consumption differed across socioeconomic subgroups and over time (2010–2018) in Korea. Cross-sectional data from the Korea National Health and Nutrition Examination Survey 2010–2018 were analyzed. Food and beverages reported in a one-day 24 h recall were classified according to the NOVA food classification criteria. The dietary energy contribution of ultra-processed foods was high among men and urban residents, and increased with education and income level; additionally, it reached its peak in adolescents and thereafter decreased with increasing age. After adjusting the socioeconomic variables, such associations remained significant, except for income level. The overall contribution of ultra-processed foods increased from 23.1% (2010–2012) to 26.1% (2016–2018), and the same trend over time was observed in all age groups and socioeconomic strata. In the Korean population, ultra-processed food consumption differed by individual socioeconomic characteristics, but gradually increased over time, and this trend was consistently found in all socioeconomic subgroups. Future strategies to promote healthy food choices are needed for the Korean population.

Background Food environments have changed rapidly, and the global interest in ultraprocessed foods has increased. Ultra-processed foods are typically energy dense, high in sugars and fat, and low in fiber, protein, minerals, and vitamins.Objective This study aimed to estimate the energy contribution of ultra-processed foods in the diet of Korean adults and to examine the association between ultraprocessed food consumption and dietary intake and diet quality.Design This study is a secondary analysis of cross-sectional data from the Korea National Health and Nutrition Examination Survey (2016e2018).Participants/settings A total of 16,657 adults aged 19 years who completed a 1-day 24-hour recall.Main outcome measures Absolute and relative intake of energy and nutrients were measured and dietary quality was assessed using the Korean Healthy Eating Index (KHEI).Statistical analysis Multiple regression models adjusted for sociodemographic variables were used to examine the association between quintiles of ultra-processed foods dietary energy contribution and dietary intake and quality.Results Mean reported daily energy intake was 2,031 kcal, with 25.1% of calories coming from ultra-processed foods. Mean energy contribution from ultra-processed foods ranged from 3.6% kcal (Q1) to 52.4% kcal (Q5). Energy contribution of ultraprocessed foods was positively associated with reported intake of daily energy, total sugars, and total and saturated fat and inversely associated with reported intake of carbohydrates, fiber, minerals, and vitamins. Both sodium and potassium were negatively associated with percentage of energy from ultra-processed foods. However, the sodium-to-potassium ratio was high regardless of quintile of energy contribution from ultra-processed foods, and the ratio was positively associated with percentage of total energy from ultra-processed foods. Although the KHEI score was inversely associated with percentage of daily energy from ultra-processed foods, all levels of ultra-processed food consumption were associated with poor diet quality. ConclusionsThe ultra-processed foods consumption of Korean adults accounted for one fourth of daily energy intake, and a higher dietary energy contribution from ultraprocessed foods was associated with poorer dietary intakes and a lower dietary quality. Further studies are needed to understand factors influencing selection and consumption of ultra-processed foods and to identify effective strategies to promote healthy food choices.