This study examined the nutrient intake of Korean adults by considering the lunch type, categorized as home meals (HM), eating out (EO), and institutional meals (IM). Data was obtained from the 2019 Korea National Health and Nutrition Examination Survey (KNHANES). Totally, 3,786 adults (1,643 men, and 2,143 women) aged between 19-64 years were included in the study. Subjects with daily energy intake of less than 500 kcal or over 5,000 kcal, and those who skipped lunch, were excluded. The percentage of subjects in the HM, EO, and IM were 31.9, 53.6, and 14.4%, respectively. The daily energy intakes of the HM, EO, and IM groups were determined to be 2,185, 2,360, and 2,339 kcal, respectively, in men, and 1,622, 1,731, and 1,741 kcal, respectively, in women. Among the three groups, men in the EO group had more intake of fat, saturated fat, cholesterol, sodium, and riboflavin, and less dietary fiber, and whereas women consumed more fat and less dietary fiber and potassium. In the IM group, the men consumed more dietary fiber, potassium, and thiamine, whereas consumption of carbohydrate, unsaturated fatty acid, sodium, potassium, and thiamine was more in women. Energy contributions of carbohydrate, protein, and fat were all within the AMDR (acceptable macronutrient distribution ranges) for all lunch types, except for the percent of energy provided from saturated fat in EO (7.4% in men, and 8.2% in women). Our results indicate that the dietary habit of frequently eating out increases the fat intake, thereby resulting in increased health risks for adults. Thus, implementation of a nutritional education program to encourage balanced dietary habits is required to improve the nutritional status of individuals eating out.