The Tai model allows flexibility in experimental conditions, which means, in the case of the glucose-response curve, samples can be taken with differing time intervals and total area under the curve can still be determined with precision.

The effects of meal size and frequency on thermic effect of food (TEF) were examined in seven healthy normal-weight young women. Each volunteer consumed in random order one of two identical meals [3138 kJ (750 kcal), 54.5% carbohydrate, 14.0% protein, 31.5% fat]. One meal was taken over 10 min [large meal (LM)] whereas the other was taken in six equal portions of 523 kJ (125 kcal) at 30-min intervals over a 3-h period [small meals (SM)]. Metabolic rate was measured for 1 h before and every 30 min after the meal started for 5 h. When expressed as either kJ/min (kcal/min) or kJ/5h (kcal/5h), TEF was significantly higher in the LM day than in the SM day (P less than 0.05). We conclude that the temporal pattern in which a mixed caloric load is eaten affects the thermogenic response and may be an important determinant of energy balance after a meal.

No abstract

The effect of the menstrual cycle on the thermic effect of food (TEF) was examined in eight healthy, normal-weight [mean +/- SD: 56.1 +/- 5.6 kg and body mass index (in kg/m2) 21.3 +/- 1.8] women aged 22-38 y. Their lean body mass and fat mass were 39.4 +/- 2.7 kg and 16.9 +/- 6.5 kg, respectively. TEF was measured on 4 separate days selected to match the four phases of a menstrual cycle: early follicular, follicular, luteal, and late luteal. The volunteers consumed a 3138-kJ liquid meal (54.5% carbohydrate, 14.0% protein, and 31.5% fat) on each test day. Resting metabolic rate was measured for 55 min before the meal and every 30 min after the start of the meal for 205 min. Although resting metabolic rate remained unchanged, there was a significant difference (P < 0.01 by ANOVA) in mean (+/- SEM) values for TEF among the four phases of the cycle: 0.94 +/- 0.05 kJ/min during the early follicular phase, 0.86 +/- 0.09 kJ/min during the follicular phase, 0.70 +/- 0.10 kJ/min during the luteal phase, and 0.76 +/- 0.07 kJ/min during the late luteal phase. TEF decreased significantly (P < 0.025 by paired t test) during postovulation (average of luteal and late luteal phases), when it was 0.73 +/- 0.07 kJ/min, compared with preovulation (average of early follicular and follicular phases), when it was 0.90 +/- 0.06 kJ/min. In conclusion, TEF decreased during the luteal phase of the menstrual cycle, possibly as a result of impairment of glucose uptake and slower transit of food through the upper gastrointestinal tract.