Leading author, Gad Saad, professor of marketing at the John Molson School of Business and holder of the Concordia University Research Chair in Evolutionary Behavioral Sciences and Darwinian Consumption says: "Our goal was to investigate how a woman's menstrual cycle impacts consumption desires, product usage, and dollars spent within the food and beautification domains."
Saad and his team held classes at Concordia University recruiting hundreds of participants, of which they chose 59 females after a careful selection process. The women were asked to keep a detailed diary over a 35-day period, listing their calorie consumption, choice of clothing, purchases and beauty habits.
When the team analyzed the women's diary entrances, they observed the emergence of a distinct pattern in terms of how long they spent doing their make-up, sun-bathed, the clothes they wore to attract sexual attention and ate highly caloric foods. The team registered a notable increase in the women's behavior towards their appearance during the fertile phase of their menstrual cycle, and that they tended to spend more money on clothes during this phase of the cycle, i.e. days 8 - 15 in a 28-day cycle.
Saad, who wrote the books 'The Evolutionary Bases of Consumption' and 'The Consuming Instinct', which investigate the biological and evolutionary roots of consumer behavior, refers to Darwin's theory, saying:
"In ancestral times, women had to focus more time on mating-related activities during the fertile phase of the menstrual cycle, when the likelihood of conception was highest. Those same psychological and physiological mechanisms now lead women to engage in greater consumption of products relevant to reproductive drives during the fertile phase of their cycle."
The daily diaries also revealed a distinct drop in food consumption during the fertile phase. In terms of food, cravings and highly caloric foods peaked during the luteal (infertile) phase of the cycle, i.e. days 16 to 28, with a strong spike in purchasing food during this phase.
According to Saad, these factors are also involved in the evolutionary forces. He explains: "Women consume more calories during the luteal phase because they've evolved psychological and physiological mechanisms that favored non-mating-related activities like food foraging during the non-fertile phase of their cycles. Different Darwin pulls, such as mating versus food, take precedence depending on a woman's menstrual status."
Even though some women may feel oppressed by evolution when they find that their calorie cravings, clothing choices and shopping purchases are shaped by the ovulatory cycle, they should still be aware of them explains Saad, continuing:
"These consumption behaviors take place without women's conscious awareness of how hormonal fluctuations affect their choices as consumers. Our research helps highlight when women are most vulnerable to succumbing to cyclical temptations for high-calorie foods and appearance-enhancing products. These findings can help women to make choices for themselves contrary to the old canard of biological determinism."
Saad believes that developing a consumption-related app may help women in tracking when they are particularly vulnerable in terms of shopping habits. For instance, women could be empowered by being made consciously aware of adverse menstrual cycle-influenced behaviors when they receive a smart-phone warning message that reads, "Today's day 24 of your cycle - avoid grocery shopping!"
Written by Petra Rattue