Resting metabolic rate and thermic effects of a sucrose-sweetened soft drink during the menstrual cycle in young Chinese women.

The resting metabolic rate (RMR) and thermic effects (TEF) of a sucrose-sweetened soft drink in a group (n = 19) of ovulating young Chinese women were determined by indirect calorimetry in the midfollicular and midluteal phases of the menstrual cycle. Urinary luteinizing hormone surge was used to confirm ovulation. The RMR was measured twice in each phase and found to be similar (F(1,18) = 0.863) across the follicular (5018 kJ/24 h) and the luteal (5098 kJ/24 h) phases. Within each phase and on separate days, subjects were given water (280 mL) or sucrose-sweetened soft drink (539 kJ). Soft drink, but not water, consumption increased energy expenditure over a period of 45 min. Compared with the follicular phase, a small but significant increase in TEF (kJ/45 min) was observed in the luteal phase (t = 2.434, p < 0.05). Energy expenditure after drinking the soft drink, however, was similar in the two phases. RMR was positively correlated with TEF (r = 0.613, p < 0.01) and net TEF (r = 0.648, p < 0.005) in the luteal but not the follicular phase. In ovulating women, the thermic effect of sucrose is influenced by the phase of the menstrual cycle.

Menstrual cycle and voluntary food intake in young Chinese women.

The effect of menstrual cycle phase on energy and macronutrients intakes was assessed in 20 university students (21.2+/-1.3 years) all of whom experienced ovulatory cycle as documented by a surge in urinary luteinizing hormone. Three-day food intake records, which consisted of one weekend day, were kept in both mid-follicular and mid-luteal phases. Mean daily energy intake was higher (p=0.02) in the luteal phase (6978+/-1847 kJ) than in the follicular phase (6095+/-1174 kJ). Intakes of carbohydrate and fat were also significantly elevated (by 15 and 21%, respectively) in the luteal phase. The menstrual phase effect on energy intake was attributed to the substantially higher intakes from Thursday through Sunday in the luteal phase. The proportion of energy from the three macronutrients was not affected by menstrual phase nor day of the week.