On Diurnal Variation of Diet-Induced Thermogenesis According to the Meal Time-Zone

1.The diurnal variation of diet-induced thermogenesis (DIT) was measured, using healthy and normoweighty subjects The subjects were 6 male young men averaged 19(]SY.+-。[)1.3years. Their physical characteristics averaged 169.2(]SY.+-。[)4.7cm in height, 57.3(]SY.+-。[)5.6kg in body weight, 19.8(]SY.+-。[)1.5in BMI, 44.0(]SY.+-。[)4.1kg in LBM and 22.2(]SY.+-。[)1.9 in %FAT.Following the measurement of their basal metabolic rates, normo-nutritive liquid diet was given at 7.40 (breakfast), 11.40 (lunch), 17.40 (supper) and 23.40 (midnight meal) each and their respective 6h (8.00-, 12.00-, 18.00-and 24.00) energy expenditures were measured. For the convenience of the measurement, experiments were carried out twice-dividedly, i.e.at breakfast and supper and at lunch and midnight meal. postprandia DIT %dose was 13.9,12.8,9.8 and 8.5%, respectively after breakfast, lunch, supperand midnight meal ; DIT showed low values after supper and midnigth meal. 2.The influence of chewing on DIT was measured The subjects were 10 male young men averaged 19.7 years. Tge base group was given test meal (normo-nutritive liquid diet) only, the chewing group being given test meal following chewing sugarless gum (873 rtimes : 25 subjucts' mean chewing times per meal), and their respective 6h-energy expenditures were measured. Post-prandial DIT % dose was greater for the chewing group (4.5%) than the base gruup (3.9%), up to 1.5h post-prandially, but showed no difference in terms of 6h. 3.Obese subjects were determined for their post-breakfast DIT The subjects were 23 obese women aged 23-66 years and of BMI 29.7(]SY.+-。[)2.8. The normo-nutritive liquid diet was given at 7.40 a.m., and their respective 4h (8.00-) energy expenditures were measured. Because of variations of DIT observed among these obese women, H (12 subjects) and L (11 subjects) groups were defined as above and below 10%, respectively, with reference of 10%, which is said to be DIT value in general.DIT % dose prove to be 13.6 and 4.3% for H and L groups, respectively, with a significant inter-group difference (p<0.05).