Consumption of highly processed foods in relation to overall diet quality among Japanese adults: a nationwide study

Abstract

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.

A Cross-Sectional Pilot Study on Association of Ready-to-Eat and Processed Food Intakes with Metabolic Factors, Serum Trans Fat and Phospholipid Fatty Acid Compositions in Healthy Japanese Adults

“…Our participants obtained approximately two-thirds of their total energy intake from processed and RTE foods, other than drinks and dairy items, thus exceeding the approximately one-third of total energy from highly/ultra-processed foods as reported in earlier Japanese studies using the NOVA system [9][10][11], suggesting that the consumption of highly processed food is rising in the younger generation in the metropolitan areas of Japan.…”

“…Furthermore, dietary ultra-processed food exposure is reportedly associated with adverse health outcomes, such as obesity, type 2 diabetes, cardiovascular disease, cancer, irritable bowel syndrome, depression, and frailty conditions, as well as increased cardiovascular and all-cause mortality [1,5]. The Japanese public has also shown an increased consumption of meals prepared outside the home, including processed and ready-to-eat foods [6,7], and these changes have made healthy eating difficult, leading to unbalanced nutrient intakes, especially for the younger generation [4,[8][9][10][11]. There is sometimes little choice, when providing nutrition education to patients with lifestyle-related diseases who cannot cook on their own, but to recommend using RTE foods.…”

Na and K Intake from Lunches Served in a Japanese Company Cafeteria and the Estimated Improvement in the Dietary Na/K Ratio Using Low-Na/K Seasonings and Dairy to Prevent Hypertension

“…The undesirable trends in Na and K intake in Japan are partially attributed to the increased use of restaurant meals, takeout, and processed foods [14], which externalizes the control of seasonings, usually resulting in a high Na content and a decreased intake of fruits and vegetables (i.e., the major sources of K) [4,15]. These changes in dietary habits may apply to the majority of the working generation in Japan because of an increase in the female employment rate [16], long working hours [17], and a decline in the number of household members [18], which has resulted in a decrease in homemade meals [19,20].…”

Na and K Intake from Lunches Served in a Japanese Company Cafeteria and the Estimated Improvement in the Dietary Na/K Ratio Using Low-Na/K Seasonings and Dairy to Prevent Hypertension

“…The undesirable trends in Na and K intake in Japan are partially attributed to the increased use of restaurant meals, takeout, and processed foods [15], which externalizes the control of seasonings, usually resulting in a high Na content and a decreased intake of fruits and vegetables (i.e., the major sources of K) [4,16]. These changes in dietary habits may apply to the majority of the working generation in Japan because of an increase in the female employment rate [17], long working hours [18], and a decline in the number of household members [19], which has resulted in a decrease in homemade meals [20,21].…”