LAUSR

OBJECTIVE To (i) examine the consumption of highly processed foods (HPFs) in relation to diet quality among Japanese adults and (ii) compare the results when dishes prepared away home are disaggregated into food ingredients before classification by processing levels and the results when they are not. DESIGN Cross-sectional analysis using 4-day dietary record data. Foods were categorised by level of processing using the framework developed by the University of North Carolina at Chapel Hill. Specifically, dishes prepared away from home were classified at both the food level (classified after disaggregation into ingredients) and dish level (classified without disaggregation). Diet quality was assessed using the Healthy Eating Index-2015 and Nutrient-Rich Food Index 9.3. SETTING Twenty areas in Japan. PARTICIPANTS Adults aged 20-69 years (n 388). RESULTS Energy contribution of HPFs was higher when dishes prepared away from home were classified at dish level than food level (48.3% vs. 32.9%, P<0.0001). Regardless of the classification method, cereals and starchy foods were the top food groups contributing to total energy intake from HPFs. After adjusting for potential confounders, participants in higher tertiles of the energy contribution of HPFs had lower total scores for Healthy Eating Index-2015 and Nutrient-Rich Food Index 9.3 (P for trend ≤0.007 for all), irrespective of the food- or dish-level classification. CONCLUSIONS HPFs account for at least one-third of energy intake of Japanese adults. Regardless of the classification methods for dishes prepared away from home, higher consumption of HPFs was associated with lower diet quality.