title: Validity and reproducibility of a novel method for time-course evaluation of diet-induced thermogenesis in a respiratory chamber.
abstract: We developed a novel method for computing diet-induced thermogenesis (DIT) in a respiratory chamber and evaluated the validity and reproducibility of the method. We hypothesized that DIT may be calculated as the difference between postprandial energy expenditure (EE) and estimated EE (sum of basal metabolic rate and physical activity (PA)-related EE). The estimated EE was derived from the regression equation between EE from respiration and PA intensity in the fasting state. It may be possible to evaluate the time course of DIT using this novel technique. In a validity study, we examined whether DIT became zero (theoretical value) for 6 h of fasting in 11 subjects. The mean value of DIT calculated by the novel and traditional methods was 22.4 ± 13.4 and 3.4 ± 31.8 kcal/6 h, respectively. In the reproducibility study, 15 adult subjects lived in the respiratory chamber for over 24 h on two occasions. The DIT over 15 h of postprandial wake time was calculated. There were no significant differences in the mean values of DIT between the two test days. The within-subject day-to-day coefficient of variation for calculated DIT with the novel and traditional methods was approximately 35% and 25%, respectively. The novel method did not have superior reproducibility compared with that of the traditional method. However when comparing the smaller variation in the fasting state than the theoretical value (zero), the novel method may be better for evaluating interindividual differences in DIT than the traditional method and also has the ability to evaluate the time-course.
authors.affiliation: Department of Nutritional Science, National Institute of Health and Nutrition National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan Japan Society for the Promotion of Science, Tokyo, Japan Department of Communication, Tokyo Woman's Christian University, Tokyo, Japan chiyoko@nih.go.jp chiyoko@lab.twcu.ac.jp.
authors.forename: Chiyoko
authors.initials: C
authors.lastname: Usui
authors.affiliation: Department of Nutritional Science, National Institute of Health and Nutrition National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ando
authors.affiliation: Department of Nutritional Science, National Institute of Health and Nutrition National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan Faculty of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ohkawara
authors.affiliation: Department of Nutritional Science, National Institute of Health and Nutrition National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan.
authors.forename: Rieko
authors.initials: R
authors.lastname: Miyake
authors.affiliation: Faculty of Service Industries, University of Marketing and Distribution Sciences, Kobe, Japan.
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Oshima
authors.affiliation: Health Care Food Research Laboratories, Kao Corporation, Tokyo, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Hibi
authors.affiliation: Health Care Food Research Laboratories, Kao Corporation, Tokyo, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Oishi
authors.affiliation: Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
authors.forename: Kumpei
authors.initials: K
authors.lastname: Tokuyama
authors.affiliation: Department of Nutritional Science, National Institute of Health and Nutrition National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan.
authors.forename: Shigeho
authors.initials: S
authors.lastname: Tanaka
keywords: Diet‐induced thermogenesis; reproducibility; respiratory chamber; triaxial accelerometry; validity