Impact of menstrual cycle on resting and postprandial metabolism in recreationally active, eumenorrheic females

The impact of the menstrual cycle on resting and postprandial metabolism is unclear. In this study, five eumenorrheic women had resting energy expenditure (REE) and substrate utilization measured at rest and after a mixed meal during three phases of the menstrual cycle (early follicular, late follicular, and mid luteal). REE was higher during mid luteal (1509 ± 143 kcal), compared to early follicular (1447 ± 94 kcal) and late follicular phases (1409 ± 89 kcal)(p = 0.38). Resting RQ did not differ across menstrual cycle phase. Diet-induced thermogenesis was higher during early follicular (35.6 ± 9.3 kcal) and late follicular (31.8 ± 11.8 kcal) versus mid luteal phase (21.1 ± 14.1 kcal)(p = 0.17). Mean postprandial RQ was higher during early and late follicular compared to mid luteal phase (p = 0.36). These preliminary findings indicate potential differences in resting and postprandial metabolism across the menstrual cycle.