Establishment of a Meal Coding System for the Characterization of Meal-Based Dietary Patterns in Japan

Background: Most studies on dietary patterns to date have focused on the daily intake of individual foods, rather than the combination of foods simultaneously consumed during specific eating occasions (breakfast, lunch, dinner, and snacks). Objective: We aimed to establish a meal coding system for characterizing meal-based dietary patterns in Japan. Methods: Dietary data used were from the 2012 National Health and Nutrition Survey, Japan, in which 1-d weighed dietary records were collected from 26,361 adults aged ≥20 y. The food diary was based on a typical Japanese eating pattern, which comprised breakfast, lunch, dinner, and snacks; these eating occasions were prescribed in the diary. A total of 94,439 eating occasions (25,187 breakfasts, 25,888 lunches, 26,248 dinners, and 17,116 snacks) were identified. For all meal types, common food group combinations were identified to produce a range of generic meals. These generic meals were then used in principal components analysis to establish meal patterns. Results: In total, 94 generic meals (24 breakfasts, 27 lunches, 26 dinners, and 17 snacks) were identified. The most frequently identified food group combination for all 3 main meals was "rice and vegetables" (9 generic meals for breakfast, 12 for lunch, and 16 for dinner), whereas "confectioneries and nonalcoholic and noncaloric beverages" was the most prevalent combination for snacks (3 generic meals). In total, 19 meal patterns were established by using principal components analysis, which accounted for 24.1% of total variance. Patterns ranged considerably with regard to meal-type inclusion and the selection of staple foods (rice, bread, and noodles) and beverages, as well as with regard to meal constituents. Conclusions: With the use of a meal coding system, we identified a wide range of meal-based dietary patterns in Japanese adults. This meal coding system may be useful in capturing and investigating the complex nature of Japanese meals and food combination patterns.