Dietary quality differs by consumption of meals prepared at home vs. outside in Korean adults

BACKGROUND/OBJECTIVES: Eating out has been reported to have negative effects on nutritional status. However, eating out can include meals prepared at home and eaten outside. Conversely, meals eaten at home can be brought from outside, as take-out and home deliveries have become common in Korea. Thus, we tested whether or not meal preparation location influences daily diet quality. SUBJECTS/METHODS: From the Korea National Health and Nutrition Examination Survey (KNHANES) 2007-2009, 4,915 Korean adults (20-64 years) were classified into two groups: home-made meal group (HMG), who ate ${\geq}2$ meals per day prepared at home (n = 4,146), and non-home-made meal group (NHMG), who ate ${\geq}2$ meals per day prepared outside home (n = 769). Daily diet quality was determined by energy intake, nutrient intake, Dietary Variety Score (DVS), and Diet Diversity Score (DDS). RESULTS: Compared to the HMG, the NHMG was more likely to consist of men, single, employed, educated and of a higher economic status (all, P < 0.01). The NHMG showed higher energy intakes (1,776 vs. 2,116 kcal/day) with higher percentages of energy from protein (15 vs. 23%) and fat (14 vs. 16%) and lower intakes of dietary fiber, phosphorus, potassium, niacin, and vitamin C (all, P < 0.01) than the HMG, with some variations among age groups. The NHMG tended to consume foods prepared by frying and grilling and had more one-dish meals such as bibimbap, noodles, and dumplings but also showed higher dietary diversity. CONCLUSIONS: It should be noted that home-made meals do not necessarily guarantee a healthy diet, and the effects of meal preparation location on nutritional status might vary depending on socio-demographic characteristics.