Energy regulation over the menstrual cycle.

To investigate the influence of ovarian hormones on energy regulation, twenty-six normal weight, noneating disordered women recorded their food consumption, exercise, and eating patterns over one menstrual cycle. Serum levels of ovarian hormones were measured to determine three menstrual cycle phases, namely perimenstrual, follicular/ovulatory, and luteal. Energy intake increased 685.9 kJ/day (p < 0.05) from the follicular/ovulatory to the luteal phase. The percent of energy intake as protein and carbohydrate was relatively constant over the three menstrual cycle phases, but the intake from fat increased 2% (p < 0.05) during the luteal phase, representing a 9.2 g/day increment. Variations in energy and fat intake over the menstrual cycle were not attributable to differences in energy expenditure through exercise or dietary restraint, and appear to be related to changes in the estrogen/progesterone ratio.