Highly Processed Food Consumption and its Association With Overall Diet Quality in a Nationwide Sample of 1,318 Japanese Children and Adolescents: A Cross-Sectional Analysis Based on 8-Day Weighed Dietary Records.

BACKGROUND: There is limited evidence regarding the association between consumption of highly processed foods (HPFs) and overall diet quality in children and adolescents from Asian countries. OBJECTIVE: This study aimed to examine the association between HPF consumption and overall diet quality in Japanese children and adolescents. DESIGN: A cross-sectional analysis was conducted based on 8-day dietary record data collected from volunteers in 32 of 47 prefectures throughout Japan in 2016 to 2020. Foods were categorized into 1 of 4 processing levels using the framework developed by the University of North Carolina at Chapel Hill. Food classification was performed under a low-estimate scenario (classifying mixed dishes consumed outside the home after disaggregation into ingredients) and high-estimate scenario (classifying them into HPFs without food disaggregation). PARTICIPANTS/SETTING: A total of 1318 Japanese children and adolescents aged 3 to 17 years participated in the study. MAIN OUTCOME MEASURES: Diet quality was assessed using the Healthy Eating Index-2020 and Nutrient-Rich Food Index 9.3. STATISTICAL ANALYSIS: Multiple regression models adjusted for sociodemographic and anthropometric characteristics and the survey cycle were used to examine the association between tertiles of the energy contribution of HPFs and diet quality. RESULTS: The mean energy contribution of HPFs was 27.3% and 44.3% in the low- and high-estimate scenarios, respectively. The top contributors to total energy intake from HPFs were confectioneries in the low-estimate scenario and cereals and starchy foods in the high-estimate scenario. Irrespective of the scenarios, participants in higher tertiles of energy contribution of HPFs had lower total scores for Healthy Eating Index-2020 and Nutrient-Rich Food Index 9.3 (P for trend < .0001). CONCLUSIONS: HPFs accounted for more than one-quarter of the energy intake of Japanese children and adolescents surveyed, and higher consumption of HPFs was associated with lower diet quality. Therefore, reducing HPF consumption may increase overall diet quality among Japanese children and adolescents. Further research is needed to explore the causal nature of this association.

Association between meal context and meal quality: an ecological momentary assessment in Japanese adults.

PURPOSE: The purpose was to assess the relationship between the quality of meals and its context. METHODS: We conducted a cross-sectional study of 222 Japanese adults aged 30-76 years in 2021. The following information was obtained from the 4-d weighed dietary records: the recording day (working or not), meal type (breakfast, lunch, or dinner), eating companions (alone or with someone), eating location (at home or away from home), and screen-based activity (yes or no). The nutritional quality of each meal was evaluated using the Healthy Eating Index 2020 (HEI-2020). RESULTS: The analysis included 1,295 meals for males and 1,317 for females. The mean HEI-2020 ranged from 43.0 (lunch) to 51.9 (dinner) in males and from 45.7 (breakfast) to 52.0 (dinner) in females. Multilevel linear regression showed that, in males, lunch had a significantly lower HEI-2020 score compared to breakfast (ß = -1.81, 95% confidence interval [CI]: -3.42, - 0.20), while dinner had a significantly higher HEI-2020 score (ß = 6.77, 95% CI: 5.34, 8.20). Eating with someone was significantly associated with a higher HEI-2020 score (ß = 2.22, 95% CI: 0.76, 3.67). Among females, dinner had a higher HEI-2020 score than breakfast (ß = 5.21, 95% CI: 3.72, 6.70). Eating away from home was associated with higher HEI-2020 scores (ß = 2.14, 95% CI: 0.04, 4.24). CONCLUSION: Meal type, location, and eating companions were associated with meal quality in this population, with differences between males and females. Incorporating these factors in nutrition education and interventions can enhance diet quality.

Prevalence and Correlates of Dietary and Nutrition Information Seeking Through Various Web-Based and Offline Media Sources Among Japanese Adults: Web-Based Cross-Sectional Study.

BACKGROUND: The advent of the internet has changed the landscape of available nutrition information. However, little is known about people's information-seeking behavior toward healthy eating and its potential consequences. OBJECTIVE: We aimed to examine the prevalence and correlates of nutrition information seeking from various web-based and offline media sources. METHODS: This cross-sectional study included 5998 Japanese adults aged 20 to 79 years participating in a web-based questionnaire survey (February and March 2023). The dependent variable was the regular use of web-based and offline media as a reliable source of nutrition information. The main independent variables included health literacy, food literacy, and diet quality, which were assessed using validated tools, as well as sociodemographic factors (sex, age, education level, and nutrition- and health-related occupations). RESULTS: The top source of nutrition information was television (1973/5998, 32.89%), followed by web searches (1333/5998, 22.22%), websites of government and medical manufacturers (997/5998, 16.62%), newspapers (901/5998, 15.02%), books and magazines (697/5998, 11.62%), and video sites (eg, YouTube; 634/5998, 10.57%). Multivariable logistic regression showed that higher health literacy was associated with higher odds of using all the individual sources examined; odds ratios (ORs) for 1-point score increase ranged from 1.27 (95% CI 1.09-1.49) to 1.81 (95% CI 1.57-2.09). By contrast, food literacy was inversely associated with the use of television (OR 0.65, 95% CI 0.55-0.77), whereas it was positively associated with the use of websites of government and medical manufacturers (OR 1.98, 95% CI 1.62-2.44), books and magazines (OR 2.09, 95% CI 1.64-2.66), and video sites (OR 1.53, 95% CI 1.19-1.96). Furthermore, diet quality was positively associated with the use of newspapers (OR 1.02, 95% CI 1.01-1.03) and books and magazines (OR 1.03, 95% CI 1.02-1.04). Being female was associated with using television and books and magazines, whereas being male was associated with using websites of government and medical manufacturers, newspapers, and video sites. Age was positively associated with using newspapers and inversely associated with using websites of government and medical manufacturers and video sites. People with higher education were more likely to refer to websites of government and medical manufacturers and newspapers but less likely to use television and video sites. Dietitians were more likely to use websites of government and medical manufacturers and books and magazines than the general public but less likely to use television and video sites. CONCLUSIONS: We identified various web-based and offline media sources regularly used by Japanese adults when seeking nutrition information, and their correlates varied widely. A lack of positive associations between the use of the top 2 major sources (television and web searches) and food literacy or diet quality is highlighted. These findings provide useful insights into the potential for developing and disseminating evidence-based health promotion materials.

Self-perceived food literacy in relation to the quality of overall diet and main meals: A cross-sectional study in Japanese adults.

This cross-sectional study aimed to assess the relationship between self-perceived food literacy (SPFL) and quality of overall diet and main meals in Japanese adults. In total, 5998 adults aged 20-79 years were included in this analysis. The SPFL was assessed using the Japanese version of the 29-item Dutch SPFL scale (score range 1-5). Using validated dietary information, the Healthy Eating Index-2015 (HEI-2015) was calculated (score range 0-100). The mean SPFL was 3.18; the internal consistency of the overall scale was considered good (Cronbach's alpha: 0.80). The mean HEI-2015 for overall diet was 50.4. The SPFL was significantly and positively associated with the HEI-2015. Using multiple linear regression, one point increase of SPFL corresponded to an increase in HEI-2015 by a point of 4.8 for overall diet, 6.2 for breakfast, 4.6 for lunch, and 3.6 for dinner (all P < 0.0001). Six of the eight domains of SPFL (i.e., food preparation skills, resilience and resistance, healthy snack styles, examining food labels, healthy budgeting, and healthy food stockpiling) were significantly associated with the HEI-2015 for overall diet. When the HEI-2015 for each meal was examined, the domains showing significant associations with all three meals included food preparation skills, healthy snack styles, and healthy budgeting. The healthy food stockpiling was associated with the HEI-2015 for breakfast and lunch, but not dinner. The social and conscious eating and daily food planning were associated with the breakfast HEI-2015 only, with the resilience and resistance associated with the dinner HEI-2015 only. In conclusion, the SPFL was cross-sectionally associated with the quality of overall diet and main meals in Japanese adults. Further observation and intervention studies are needed to confirm the associations observed here.

The Nutritional Characteristics of Usual Lunches Consumed Among Japanese Workers: Comparison Between Different Lunch-Type Groups.

OBJECTIVE: This study investigated whether the nutritional characteristics of lunches consumed by Japanese workers differ by where the meal is usually prepared or eaten. METHODS: This cross-sectional study included 620 employees (aged 20 to 75 years) from eight business offices in Tokyo, Japan. Dietary data were collected using the validated Meal-based Diet History Questionnaire. The Healthy Eating Index 2015 and dietary intakes from lunch were compared between workers classified by usual lunch type: homemade (n = 190), staff canteen (n = 77), restaurant (n = 109), and takeaway (n = 244). RESULTS: Healthy Eating Index 2015 for lunch was highest in the staff canteen group, followed by the homemade group. The staff canteen group had higher intakes of total vegetables, potatoes, fish, and several vitamins from lunch than the restaurant or takeaway groups. CONCLUSIONS: Homemade and canteen lunches are relatively healthy options for lunch for Japanese workers.

The association of highly processed food consumption with food choice values and food literacy in Japanese adults: a nationwide cross-sectional study.

BACKGROUND: Highly processed food (HPF) consumption is increasing globally and has become a prominent public health concern. However, the relationship between HPF consumption and food choice values and food literacy is unknown. This study aimed to examine the association of HPF consumption with food choice values and food literacy. METHODS: This cross-sectional study used data from a nationwide questionnaire survey conducted in 2018 among 2232 Japanese adults aged 18-80 years. We assessed eight food choice values (accessibility, convenience, health/weight control, tradition, sensory appeal, organic, comfort, and safety) using a 25-item scale, and food literacy characterised by nutrition knowledge (using a validated 143-item questionnaire), cooking and food skills (using 14- and 19-item scales, respectively), and eight eating behaviours (hunger, food responsiveness, emotional overeating, enjoyment of food, satiety responsiveness, emotional undereating, food fussiness, and slowness in eating, using the 35-item Adult Eating Behavior Questionnaire). HPF consumption was estimated using a validated brief diet history questionnaire. The associations between HPF consumption and age, body mass index, energy intake, and each score on food choice values and food literacy were evaluated by multiple linear regression. RESULTS: In males, one standard deviation increase in scores for cooking skill and satiety responsiveness was associated with an increase in HPF consumption by 22.1 g/4184 kJ (95% confidence interval (CI): 6.6 to 37.5) and 15.4 g/4184 kJ (95% CI: 6.0 to 24.7), respectively. In females, one standard deviation increase in age and scores for safety and nutrition knowledge corresponded to a decrease in HPF consumption by - 16.4 g/4184 kJ (95% CI: - 23.4 to - 9.3), - 9.9 g/4184 kJ (95% CI: - 19.1 to - 0.7), and - 11.1 g/4184 kJ (95% CI: - 17.0 to - 5.3), whereas one standard deviation increase in the satiety responsiveness score corresponded to an increase in HPF consumption by 13.1 g/4184 kJ (95% CI: 6.8 to 19.4). CONCLUSIONS: This cross-sectional study suggests that several aspects of food choice values and food literacy were associated with HPF consumption in Japanese adults. Further studies are needed to confirm our findings in a broader context.

Usual Nutrient Intake Distribution and Prevalence of Nutrient Intake Inadequacy among Japanese Children and Adults: A Nationwide Study Based on 8-Day Dietary Records.

In this cross-sectional study, we evaluated nutrient intake adequacy in 4450 Japanese people aged 1-79 years. Dietary data was collected through non-consecutive 8-day weighed dietary records. Usual nutrient intakes from foods and beverages were estimated using the Multiple Source Method. Participant proportions with intakes below and above the Japanese Dietary Reference Intakes (2020) were calculated. Usual intakes of most nutrients were below the Estimated Average Requirement; calcium showed a high percentage of inadequacy across all sex and age groups (29-88%), and iron showed a high inadequacy among females aged 12-64 years (79-95%). The percentages of energy from protein and carbohydrates, dietary fibre, and potassium were typically below the lower limit of the Tentative Dietary Goal for Preventing Lifestyle-related Diseases (DG). Furthermore, over 20% of the participants exceeded the upper limit of the DG for the percentages of energy from total and saturated fats, and over 88% exceeded the upper limit of the DG for sodium. Japanese children and adults could improve their nutrient intake by increasing calcium, iron, dietary fibre, and potassium and reducing total and saturated fats and sodium. These findings can inform policies and interventions to improve nutrient intake in Japan.

Web-Based Content on Diet and Nutrition Written in Japanese: Infodemiology Study Based on Google Trends and Google Search.

BACKGROUND: The increased availability of content of uncertain integrity obtained through the internet is a major concern. To date, however, there has been no comprehensive scrutiny of the fitness-for-purpose of web-based content on diet and nutrition. OBJECTIVE: This cross-sectional study aims to describe diet- and nutrition-related web-based content written in Japanese, identified via a systematic extraction strategy using Google Trends and Google Search. METHODS: We first identified keywords relevant for extracting web-based content (eg, blogs) on diet and nutrition written in Japanese using Google Trends. This process included identification of 638 seed terms, identification of approximately 1500 pairs of related queries (top) and search terms, the top 10% of which were extracted to identify 160 relevant pairs of related queries (top) and search terms, and identification of 107 keywords for search. We then extracted relevant web-based content using Google Search. RESULTS: The content (N=1703) examined here was extracted following a search based on 107 keywords. The most common themes included food and beverages (390/1703, 22.9%), weight management (366/1703, 21.49%), health benefits (261/1703, 15.33%), and healthy eating (235/1703, 13.8%). The main disseminators were information technology companies and mass media (474/1703, 27.83%), food manufacturers (246/1703, 14.45%), other (236/1703, 13.86%), and medical institutions (214/1703, 12.57%). Less than half of the content (790/1703, 46.39%) clearly indicated the involvement of editors or writers. More than half of the content (983/1703, 57.72%) was accompanied by one or more types of advertisement. The proportion of content with any type of citation reference was 40.05% (682/1703). The themes and disseminators of content were significantly associated with the involvement of editors or writers, accompaniment with advertisement, and citation of reference. In particular, content focusing on weight management was more likely to clearly indicate the involvement of editors or writers (212/366, 57.9%) and to be accompanied by advertisement (273/366, 74.6%), but less likely to have references cited (128/366, 35%). Content from medical institutions was less likely to have citation references (62/214, 29%). CONCLUSIONS: This study highlights concerns regarding the authorship, conflicts of interest (advertising), and the scientific credibility of web-based diet- and nutrition-related information written in Japanese. Nutrition professionals and experts should take these findings seriously because exposure to nutritional information that lacks context or seems contradictory can lead to confusion and backlash among consumers. However, more research is needed to draw firm conclusions about the accuracy and quality of web-based diet- and nutrition-related content and whether similar results can be obtained in other major mass media or social media outlets and even other languages.

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

OBJECTIVE: To (i) examine the consumption of highly processed foods (HPF) 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 HPF was higher when dishes prepared away from home were classified at dish level than food level (48·3 % v. 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 HPF. After adjusting for potential confounders, participants in higher tertiles of the energy contribution of HPF 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: HPF accounted 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 HPF was associated with lower diet quality.

Associations of food choice values and food literacy with overall diet quality: a nationwide cross-sectional study in Japanese adults.

To date, a limited number of studies have examined aspects of food choice values and food literacy in relation to some aspects of dietary behaviours. The aim of this cross-sectional study was to comprehensively examine the associations of food choice values and food literacy with diet quality. In total, 2231 Japanese adults aged 19-80 years completed questionnaires asking about food choice values (accessibility, convenience, health/weight control, tradition, sensory appeal, organic, comfort and safety) and food literacy characterised by nutrition knowledge, cooking skills, food skills and eating behaviours (hunger, food responsiveness, emotional overeating, enjoyment of food, satiety responsiveness, emotional undereating, food fussiness and slowness in eating). As a measure of diet quality, the Healthy Eating Index-2015 (HEI-2015) was calculated using a brief-type diet history questionnaire (BDHQ) or a food combination questionnaire (FCQ). In males, after adjustment for potential confounding factors (including age, BMI and the ratio of reported energy intake to estimated energy requirement), the HEI-2015 derived from BDHQ and that derived from FCQ were associated significantly (P ≤ 0·02) and positively with the food choice values of organic and inversely with food fussiness. In females, the HEI-2015 showed positive associations with the food choice values of health/weight control, nutrition knowledge and cooking skills and an inverse association with food fussiness, irrespective of the dietary assessment questionnaire (P ≤ 0·03). In conclusion, this study suggests that several aspects of food choice values and food literacy were associated with diet quality, and the aspects related differed between males and females.

Highly Processed Food Consumption and Its Association with Anthropometric, Sociodemographic, and Behavioral Characteristics in a Nationwide Sample of 2742 Japanese Adults: An Analysis Based on 8-Day Weighed Dietary Records.

This cross-sectional study assessed highly processed food (HPF) consumption and its association with individual characteristics in a nationwide sample of Japanese adults. Eight-day weighed dietary records were obtained from 2742 free-living adults aged 18-79 years across Japan. HPFs were identified based on a classification method developed by researchers at the University of North Carolina at Chapel Hill. The basic characteristics of the participants were assessed using a questionnaire. On average, HPF contributed to 27.9% of daily energy intake. The contribution of HPF to the daily intake of 31 nutrients ranged from 5.7% for vitamin C to 99.8% for alcohol (median, 19.9%). Cereals and starchy foods were the main food groups that contributed to the total energy intake of HPF. Multiple regression analysis showed that the older group (60-79 years) had a lower HPF energy contribution than the younger group (18-39 y) (regression coefficient (ß) = -3.55, p < 0.0001). Compared to current smokers, past and never-smokers had lower HPF energy contributions (ß = -1.41, p < 0.02; and -4.20, p < 0.0001, respectively). In conclusion, HPFs account for approximately one-third of energy intake in Japan. Younger age and current smoking status should be considered in future intervention strategies to reduce HPF consumption.

Development of a Diet Quality Score for Japanese and Comparison With Existing Diet Quality Scores Regarding Inadequacy of Nutrient Intake.

BACKGROUND: Few studies have explored optimal diet quality scores in Japan. OBJECTIVES: We developed a Diet Quality Score for Japanese (DQSJ) and examined the associations of DQSJ and existing diet quality scores with inadequacy of nutrient intake in Japanese adults. METHODS: Candidate components of the DQSJ were extracted from well-established diet quality scores: Healthy Eating Index-2015 (HEI-2015), Alternate Healthy Eating Index-2010 (AHEI-2010), Alternate Mediterranean Diet score (AMED), and Dietary Approaches to Stop Hypertension (DASH). From candidates, we selected the components of the DQSJ, considering potential health effects of the components (from the Global Burden of Disease Study) and dietary intake in Japan. The DQSJ included 10 components: fruits, vegetables, whole grain, dairy, nuts, legumes, fish, red and processed meat, sugar-sweetened beverages, and sodium. We calculated the DQSJ, HEI-2015, AHEI-2010, AMED, DASH, and Japanese Food Guide Spinning Top score (JFGST) based on 4-d dietary records of 392 Japanese aged 20-69 y. Inadequate intakes of 21 nutrients were assessed using the DRIs for Japanese. Logistic regression was used to examine the prevalence of inadequate nutrient intake according to quartiles of the scores. RESULTS: All examined scores except the JFGST were moderately to strongly correlated with each other (Spearman correlation coefficients: 0.52-0.84). They were inversely associated with the prevalence of inadequate intake of most nutrients (n = 16 for DQSJ and HEI-2015, n = 13 for AHEI-2010 and DASH, n = 17 for AMED, compared with n = 4 for JFGST). AMED was also positively associated with the prevalence of inadequate sodium intake, whereas no such associations were observed for the other scores. CONCLUSIONS: Similar to HEI-2015, AHEI-2010, and DASH, the DQSJ was generally associated with the low prevalence of inadequate intake of most nutrients in Japanese adults. Further evaluations against biomarkers and health outcomes are warranted.

Food combination questionnaire for Japanese: relative validity regarding food and nutrient intake and overall diet quality against the 4-day weighed dietary record.

The aim of this cross-sectional study was to examine the relative validity of food and nutrient intakes and overall diet quality scores derived using a newly developed dietary assessment questionnaire (food combination questionnaire, FCQ). Dietary data were collected from 222 Japanese adults (111 for each sex) aged 30-76 years using the online FCQ and then the 4-non-consective-day weighed dietary record (DR). The median of Spearman correlation coefficients for sixteen food groups was 0⋅32 among women and 0⋅38 among men. The median of Pearson correlation coefficients for forty-six nutrients was 0⋅34 among women and 0⋅31 among men. The Pearson correlation coefficient between the total scores of Healthy Eating Index-2015 (HEI-2015) derived from the DR and FCQ was 0⋅37 among women and 0⋅39 among men. The corresponding value for the Nutrient-Rich Food Index 9.3 (NRF9.3) total scores was 0⋅39 among women and 0⋅46 among men. Bland-Altman plots for these diet quality scores showed poor agreement at the individual level, although mean difference was small for the HEI-2015 (but not NRF9.3). Similar results were obtained using the paper version of FCQ, which was answered after conducting the DR, except for somewhat high Pearson correlation coefficients for the total scores of HEI-2015 (0⋅50 among both women and men) and NRF9.3 (0⋅37 among women and 0⋅53 among men). In conclusion, this analysis may lend support to the possible use of the FCQ as a rapid dietary assessment tool in large-scale epidemiologic studies in Japan, but further refinement of this tool should be pursued.

Relative validity of the online Meal-based Diet History Questionnaire for evaluating the overall diet quality and quality of each meal type in Japanese adults.

The aim of this study was to examine the relative validity of the online Meal-based Diet History Questionnaire (MDHQ) for assessing the overall diet quality and quality of each meal type (breakfast, lunch, dinner and snacks). In total, 222 Japanese adults (111 for each sex) aged 30-76 years completed the online MDHQ and then the 4-non-consecutive-day weighed dietary record (DR). The diet quality was assessed using the Healthy Eating Index-2015 (HEI-2015) and Nutrient-Rich Food Index 9.3 (NRF9.3). For the HEI-2015, compared with the DR, the MDHQ provided high median values for breakfast (in women only) and dinner and low median values for snacks. There were no significant differences observed for overall diet and lunch. For the NRF9.3, the MDHQ provided higher median values for breakfast and dinner and a lower median value for overall diet than the DR in women, with no significant differences for lunch and snacks. In men, no significant difference was observed, except for overall diet (the MDHQ providing a lower median value). For the HEI-2015, median Spearman correlation coefficient was 0·43, with a range from 0·12 (snacks in women) to 0·68 (breakfast in men). For the NRF9.3, median Spearman correlation coefficient was 0·47, with a range from 0·26 (snacks in men) to 0·65 (breakfast in men). Bland-Altman plots showed wide limits of agreement and, in some cases, proportional bias. In conclusion, the online MDHQ showed an acceptable ability for ranking individuals according to the quality of overall diet, breakfast, lunch and dinner, but not snacks.

Accuracy of estimates of serving size using digitally displayed food photographs among Japanese adults.

We evaluated the accuracy of the estimated serving size using digital photographs in a newly developed food atlas. From 209 food items in the food atlas, we selected 14 items with various appearances for evaluation. At the study site, fifty-four participants aged 18-33 years were served fourteen foods in the amount they usually ate. After they left, each food item was weighed by a researcher. The following day, the participants estimated the quantity of each food they served based on food photographs using a web-based questionnaire. We compared the weights of the foods the participants served (true serving sizes) and those determined based on the photographs (estimated serving sizes). For ten of the fourteen food items, significant differences were observed between the estimated and true serving sizes, ranging from a 29⋅8 % underestimation (curry sauce) to a 34⋅0 % overestimation (margarine). On average, the relative difference was 8⋅8 %. Overall, 51⋅6 % of the participants were within ±25 % of the true serving size, 81⋅9 % were within ±50 % and 93⋅4 % were within ±75 %. Bland-Altman plots showed wide limits of agreement and increased variances with larger serving sizes for most food items. Overall, no association was found between estimation errors and participant characteristics. The food atlas has shown potential for assessment of portion size estimation. Further development, refinement and testing are needed to improve the usefulness of the digital food photographic atlas as a portion size estimation aid.

Relative Validity of the Meal-Based Diet History Questionnaire for Estimating Nutrient Intake among Japanese Women and Men aged 30-76 Years.

The purpose of this study was to examine the relative validity of the Meal-based Diet History Questionnaire (MDHQ) for estimating nutrient intake. Dietary data were obtained from 111 Japanese women and 111 Japanese men, using the online MDHQ and the 4-non-consecutive-day weighed dietary record (DR). The number of nutrients (total n = 46) showing no significant mean differences between estimates from the online MDHQ and DR (with energy adjustment by the density model) was 17 among women and 12 among men. The median value (25th and 75th percentiles) of the Pearson correlation coefficients between the online MDHQ and DR estimates was 0.54 (0.35-0.57) among women and 0.45 (0.25-0.53) among men. Bland-Altman plots for energy-providing nutrients indicated wide limits of agreement (and proportional bias for protein) with overall underestimation of protein and fat and overestimation of carbohydrate by the online MDHQ. Similar results were found when the paper version of the MDHQ (completed after the DR) was examined. For example, the median value of the Pearson correlation coefficients was 0.54 for women and 0.45 for men. This study suggests that the MDHQ has an acceptable ability to rank individuals according to intakes of a wide range of nutrients.

Relative Validity of Food Intake in Each Meal Type and Overall Food Intake Derived Using the Meal-Based Diet History Questionnaire against the 4-Day Weighed Dietary Record in Japanese Adults.

We examined the relative validity of food intake for each meal type (breakfast, lunch, dinner, and snacks) and overall food intake obtained through the Meal-based Diet History Questionnaire (MDHQ). In total, 222 Japanese adults (111 for each sex) aged 30-76 years completed the web version of the MDHQ and then the 4-non-consecutive-day weighed dietary record (DR). The number of major food groups (n = 24 in total) for which no statistically significant difference was observed between median intakes estimated using the DR and MDHQ ranged from 8 (snacks) to 12 (dinner) among women, and from 8 (breakfast) to 13 (lunch) among men. The median values of the Spearman's correlation coefficients between the MDHQ and DR estimates ranged from 0.28 (dinner) to 0.54 (breakfast) among women, and from 0.24 (dinner) and 0.60 (breakfast) among men. Bland-Altman analyses generally showed wide limits of agreement and proportional bias. Similar results were obtained using the paper version of the MDHQ, which was completed after conducting the DR. In conclusion, the MDHQ has a satisfactory ability to estimate median intake and rank individuals according to consumption for many food groups, despite a limited ability to estimate food group intakes on an individual level.

Development of a Digital Photographic Food Atlas as a Portion Size Estimation Aid in Japan.

This study aimed to develop a digital photographic food atlas as a portion size estimation aid. Commonly consumed foods were identified from the 5512-day weighed dietary records of 644 Japanese adults. Portion sizes were determined based on the market research and distribution of food consumption in the dietary records. Each food item was classified into one of two photo types: a series of photographs showing gradually increasing portion sizes or guide photographs representing a range of portion sizes and food varieties in one photograph. Photographs of the food were taken at an angle of 42°, along with appropriate reference objects such as chopsticks. In total, 209 food and dish items were included in the food atlas. Series of photographs were taken for 105 items that are not usually served in predetermined amounts (e.g., rice and pasta), whereas guide photographs were taken for 104 items usually served in predetermined amounts (e.g., bananas and cookies). Moreover, photographs were taken for 12 kinds of household measurement items, such as cups and glasses. The food atlas could be a valuable tool for estimating the portion size in dietary surveys. Evaluating the validity of this food atlas for portion size estimation is warranted.

Food Choice Values and Food Literacy in a Nationwide Sample of Japanese Adults: Associations with Sex, Age, and Body Mass Index.

This cross-sectional study of 2231 Japanese adults described food choice values and food literacy in relation to sex, age, and body mass index. We assessed eight food choice values (accessibility, convenience, health/weight control, tradition, sensory appeal, organic, comfort, and safety, using a 25-item scale), as well as food literacy, which was characterized by nutrition knowledge (using a validated 143-item questionnaire), cooking and food skills (using 14- and 19-item scales, respectively), and eight eating behaviors (hunger, food responsiveness, emotional overeating, enjoyment of food, satiety responsiveness, emotional undereating, food fussiness, and slowness in eating, using the 35-item Adult Eating Behavior Questionnaire). Females had higher means of all the variables than males, except for food fussiness. Compared to participants aged 19-39 and/or 40-59 years, those aged 60-80 years had low means of some food choice values (accessibility, convenience, sensory appeal, and comfort), nutrition knowledge, and all the food approach behaviors (hunger, food responsiveness, emotional overeating, and enjoyment of food) and high means of other food choice values (tradition, organic, and safety) and slowness in eating. Age was inversely associated with cooking and food skills in males, whereas the opposite was observed in females. The associations with body mass index were generally weak. These findings serve as both a reference and an indication for future research.