MAKIKO NAKADE

Background/Objectives: School-aged children in Japan receive food and nutrition education (shokuiku) to promote well-balanced dietary habits. However, among high school students, the association between current well-balanced diets and shokuiku during elementary school years has not been analysed. Herein, we examined the associations between recollections of shokuiku during childhood, current well-balanced dietary habits, and eating and lifestyle behaviours among Japanese high school students, with a particular focus on sex differences. Methods: Overall, 254 second-year high school students (56.3% female) at a public high school in the Hyogo Prefecture, Japan, were included. A hypothetical model was constructed using factors potentially associated with well-balanced dietary habits (i.e., consumption of balanced meals at least twice daily), including recollections of shokuiku during elementary school (education on nutritional balance based on the 'three food groups', major nutrients' role, and breakfast importance) and current eating and lifestyle behaviours. Simultaneous sex-based multi-population analysis was performed. Results: The model demonstrated good fit (GFI = 0.944, AGFI = 0.903, CFI = 0.982, RMSEA = 0.036, and AIC = 145.174). Among female students, current well-balanced dietary habits showed significant positive associations with shokuiku (standardised estimate, female: 0.22, p = 0.005 vs. male: -0.07, p = 0.46), frequency of rice consumption (0.22, p = 0.016 vs. 0.13, p = 0.15), and eating meals with family (0.22, p = 0.003 vs. 0.36, p < 0.001). Conversely, bedtime (-0.28, p < 0.001 vs. -0.03, p = 0.72) showed a significant negative association. Among male students, only eating meals with family showed a significant positive association with current well-balanced dietary habits. Conclusions: Current well-balanced dietary habits among female high school students may be positively associated with shokuiku. Eating rice and meals with family was conducive to well-balanced dietary habits, unlike late bedtime.

Background/Objectives: In Japan, well-balanced meals composed of staple grains, protein-rich main dishes, and vegetable sides are recommended. However, issues such as infrequent breakfast consumption and poor vegetable intake persist. Obesity and non-communicable disease (NCD) rates from age 40 have also begun rising. Therefore, we investigated the structural associations between healthy diets and weight control for NCD prevention, including the potential associations with rice consumption and eating out/home meal replacement use in middle-aged Japanese individuals. Methods: This study was a cross-sectional survey based on data from 577 respondents to the 2016 Hyogo Diet Survey, Hyogo Prefecture, Japan, aged 40-59 years. A healthy diet was defined as including at least two well-balanced meals daily, eating breakfast regularly, and eating five or more vegetable dishes daily. A hypothetical model included factors associated with healthy diets and maintaining a healthy weight (energy, salt, fat, and sugar intake; using nutritional fact labels; and regular exercise), and the frequencies of rice consumption and eating out/home-meal replacement. A simultaneous multi-population analysis by sex was performed. Results: Simultaneous multi-population analysis showed acceptable goodness-of-fit. Maintaining appropriate weight and eating rice were positively associated with healthy diet scores in both sexes. However, for men, using home meal replacements was negatively associated. Conclusions: Among middle-aged Japanese in Hyogo Prefecture, weight control for NCD prevention and rice consumption were linked to healthy diets. In men, using home meal replacements was associated with worse diet quality.

Background/Objectives: In a demographic increasingly at risk of obesity and hypertension, whether dietary behaviours associated with hypertension prevention, such as restricting salt intake and consuming potassium-rich fruits and vegetables, contribute to obesity prevention is unclear. Therefore, we aimed to investigate the structural associations of dietary salt restriction practices with body mass index (BMI) and the mediating role of the dietary sodium/potassium (Na/K) ratio in middle-aged and older Japanese adults. Methods: This cross-sectional survey included 418 participants aged 40-69 years, residing in Hyogo, Japan. Simultaneous multi-population analysis according to sex was performed using a hypothetical model to explore associations of dietary salt restriction practices with BMI, mediated by the dietary Na/K ratio, as well as the role of BMI-related eating behaviours. Results: Dietary salt restriction was associated with a low dietary Na/K ratio (standardised estimate: -0.21, p = 0.001 for men; -0.19, p = 0.002 for women) in both sexes. Dietary salt restriction was associated with lower values of BMI in men (0.21, p = 0.004), mediated by the Na/K ratio; a direct but relatively weak association with lower values of BMI was observed in women (-0.16, p = 0.018). In men, eating out frequently was associated with higher values of BMI (0.20, p = 0.005). Conclusions: Dietary salt restriction practices in middle-aged and older adults may contribute to obesity prevention, and dietary Na/K ratio may play a mediating role in men but not in women; additionally, eating out was associated with higher values of BMI in men.