Does Menstruation Affect a Woman’s Metabolism?

As research continues to grow, we're finally getting more answers to how women's bodies change during their menstrual cycle.

New studies show that the hormones controlling hunger and fullness do fluctuate throughout the cycle, and there are small changes in metabolism — though not as dramatic as some might think.

Researchers studied two groups of women: those on hormonal contraceptives and those who weren't. They looked at two phases: the follicular phase (the start of the cycle) and the luteal phase (after ovulation). For women on contraceptives, they also tested both on active pills and during placebo days.

The findings? Metabolism increases by about 50 calories a day during the luteal phase, likely due to higher progesterone levels. However, there weren’t significant changes at other points in the cycle. Women on contraceptives didn’t show big differences in metabolism throughout the month, suggesting the pills might help keep hormone levels stable.

For women not on contraceptives, hormones like insulin and leptin (which regulate appetite) are higher during the luteal phase. This may explain why some women feel hungrier during this time. But women on contraceptives didn’t experience the same changes.

Other research shows that water retention and slight weight gain tend to happen later in the cycle. This is because rising progesterone levels trigger another hormone, aldosterone, which causes your body to hold onto more sodium, leading to temporary water retention. The good news? These changes usually return to normal soon after.

So, while your metabolism and weight might shift a little during your cycle, it doesn’t mean you're gaining fat. It's just a temporary response to your body’s natural hormone fluctuations.