It’s not your imagination. Women really do eat more between periods.
The time of the month does have an impact on women’s eating, shopping and beautification behavior, according to a new study at Concordia University in Montreal.
Like it or not, it’s an evolutionary fact.
“Menstrual-related hormones shape women’s daily choices,” says Prof. Gad Saad, who holds the Concordia
University Research Chair in Evolutionary Behavioral Sciences and Darwinian Consumption. “Your menstrual cycle affects many of your most fundamental survival and mating pursuits.”
Researchers tracked the daily desires, preferences and purchases of 59 women over 35 continuous days. The women kept detailed diaries of the food they ate, what they bought, and how much time they spent making themselves beautiful.
There was a marked increase in women’s appearance-related behaviours, such as putting on makeup and wearing sexy clothes, during the fertile stage of the menstrual cycle, approximately days 8 to 15 in a 28-day cycle.
There was a rise in eating and buying high-calorie food during the infertile (luteal) phase of the menstrual cycle, approximately days 16-28.
Prof. Saad and colleagues offered a Darwinian explanation: In order for the species to survive, women had to spend more time on sex-related activities while they were fertile.
Non-mating-related activities such as food foraging took precedence during the non-fertile phase.
What do we learn from this?
One lesson is that “the likelihood of being able to stick to a diet will likely wax and wane depending on a woman’s menstrual status,” says Prof. Saad.
He envisions an app that Darwin couldn’t have predicted.
“Your smart phone could warn, ‘today’s day 24 of your cycle — avoid grocery shopping’!”