Caloric load, rather than just fasting, appears to be the critical factor influencing a woman's cycle in response to dietary interventions.

“if you are a female and you are having regular menstrual cycles that is a fairly consistent duration-- so maybe it's 21 days, maybe it's 35, or anywhere in between, but it's fairly consistent from month to month-- and you are following intermittent fasting, time-restricted feeding well then chances are pretty good that it's not disrupting your fertility and likelihood of fertilization and a healthy pregnancy.”

“and for non-athletes or recreational exercises sounds like women if they distribute their calories across 12 hours are less likely to lose their menstrual cycle”

“It seems as though it's the actual caloric load that's important. So, if you're restricting your calories, at the same time, it seems like...”

“For one, it seems as though that intermittent fasting in the context of certainly daily time-restricted eating, and perhaps even, you know, doing a 24-hour fast or 48-hour fast, shouldn't have much of an effect in most women that aren't calorically-restricting, in addition to that. And perhaps aren't, you know, running marathons or, you know, running 15-miles a day.”