Aim: To investigate the characteristics of children's masticatory behavior and the associated factors by measuring the number of chews and time taken for eating the test meal.
Setting and subject: A cross-sectional observation on 61 children (5-6 years old) from two kindergartens.
Methods: The number of chews [= NC] and time taken for eating the test meal [= MT (minutes)] of a usual school lunch menu were measured by a portable chewing counter. The occlusal force was also assessed by a dental prescale, and a questionnaire was given to their guardians on their daily masticatory behavior. We formulated the “time-adjusted number of chews” [= adjusted-NC] to consider the influence of MT by the residue method and to provide a new indicator for inter-individual variation in masticatory behavior.
Results: Adjusted-NC was significantly associated with the degree of obesity (r = -0.28; p = 0.041), while MT was negatively associated with the body height (r = -0.31; p = 0.018), body weight (r = -0.30; p = 0.026) and degree of obesity (r = -0.27; p = 0.047). A multiple-regression analysis (stepwise method) showed a positive association between the guardians' behavior of “choosing ingredients for meals and snacks with consideration to facilitate their child chewing well” and adjusted-NC. The guardians' judgment on children “frequently keeping food in their mouth without soon swallowing” was positively associated with MT (r = 0.35; p = 0.010), and “eating without chewing well” was negatively associated with MT (r = -0.33; p = 0.011). No associations with other factors were apparent for the occlusal force.
Conclusions: Obese children were likely to eat faster and chew less, and that children with a small body frame were likely to spend more time with larger NC for the test meal. The guardians' attitude to food choice was associated with the measured children's masticatory behavior. The figure for adjusted-NC measured with the test meal, which was associated with obesity and other factors, can be utilized for relevant researches, and can provide a piece of evidence to improve the practices in nutrition education targeting the children's masticatory behavior.

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This study reports an analysis of the correlation between the body sizes of students and annual mean temperature data derived from the Mesh climatic data of 47 prefectures in Japan. There was a significant correlation between the annual mean temperature and body size: the lower the temperature, the larger the body size. Such factors as regional differences in the nutrition intake and genetic adaptation of Bergmann's rule were considered to explain the regional correlation of temperature and body size. However, the physiological decrease in food intake caused by the inhibiting effect of temperature was regarded as the most plausible reason. This was reinforced by the differences in nutrition intake across the regions being homogeneous. The inhibiting effect of temperature on food intake is therefore considered to be the dominant reason behind the regional difference of body size in Japan.

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The energy level was determined of a healthy menu provided in the cafeteria of a worksite aiming at the workers' weight control. The lunch selection in the cafeteria and physical status of the workers, whose BMI was 24 kg/m² or higher and who had participated in a nutrition education program for the purpose of losing weight, were examined. The workers had been classified into the Weight Reduction Group or Weight Maintenance/Gain Group by their weight change during the program, and the energy level and nutrient content of the meals selected were compared between the two groups. The average energy levels of the selected meals were 676 ± 73 kcal and 709 ± 64 kcal for the Weight Reduction Group and Weight Maintenance/Gain Group, respectively, the difference being significant. Protein, fat, and the fat energy ratio were also significantly lower for the Weight Reduction Group than for the Weight Maintenance/Gain Group. The distribution of the energy provided by the selected meals examined in 100-kcal intervals shows that the meals selected by the Weight Reduction Group were most frequently in the range of 600-700 kcal, while those by the Weight Maintenance/Gain Group were in the 700-800 kcal range.

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