Women using active combined oral contraceptive pills reported modest but consistent increases in emotional eating compared to inactive pill days, offering new insight into how synthetic hormones can influence eating behaviors.
Study: Combined oral contraceptive use and overeating. Image credit: Kopytin Georgy/Shutterstock.com
Recent article published in the journal JAMA Network Open suggests that combined oral contraceptives (COCs) are associated with increased emotional eating, associated with binge eating, perhaps because they ensure the presence of synthetic estrogen and progestin at the same time.
Emotional consumption during active pill use
Binge eating is a defining feature of the most common eating disorders, including bulimia nervosa and binge eating disorder. Understanding what drives this behavior is an important step toward prevention, particularly because these disorders disproportionately affect girls and women, often co-occur with conditions such as depression and substance use, and are associated with significant health complications.
A growing body of research has pointed to the role of endogenous ovarian hormones in binge eating. Previous studies have shown that food intake, binge eating, and emotional eating tend to increase after ovulation, when estradiol remains modestly elevated alongside high progesterone levels. Conversely, the preovulatory phase, when estradiol is high and progesterone is low, is associated with lower levels of binge eating and emotional eating.
Importantly, these hormonal associations remained independent of body mass index (BMI), negative mood, dietary restriction, or impulsivity. Similar findings were observed in both clinical and population-based samples and across the spectrum of binge eating severity, suggesting that the relationship between ovarian hormones and binge eating extends beyond individuals with diagnosed eating disorders.
The findings also align with decades of animal research showing that increased estradiol and progesterone together are associated with increased food intake. While estrogen generally suppresses appetite, progesterone appears to counteract this effect, promoting food intake.
Despite mounting evidence, researchers had not previously examined whether combined oral contraceptives (COCs), which provide both synthetic estrogen and progestin during active pill use, affect emotional or binge eating. Because active COC pills mimic the hormonal combination previously linked to greater risk of binge eating, they provide a unique opportunity to investigate these associations. Most COC regimens consist of 21 days of active hormone pills followed by seven placebo or inactive pills, allowing researchers to compare the same person’s eating behaviors during periods with and without hormone exposure.
To investigate this, researchers followed 422 women from the University of Michigan Twin Registry who were already using monophasic COCs, the most commonly prescribed formulation, which provides a fixed dose of synthetic estrogen and progestin for 21 days of active pills. Participants completed daily assessments for 49 consecutive days, allowing researchers to compare self-reported emotional eating, a well-established correlate of binge eating, during the active and inactive pill phases, while minimizing differences between participants that might otherwise influence the results.
In addition to emotional eating, the researchers looked at changes in weight preoccupation, a measure that previous studies have not found to be associated with fluctuations in ovarian hormones, to determine whether any observed effects were specific to emotional eating.
Active pills are associated with higher emotional consumption
The results showed that women were more likely to experience increased emotional eating while taking active versus inactive pills over two consecutive cycles. The increase in emotional eating was statistically significant but modest, and the magnitude of the association decreased somewhat during the second cycle.
The authors suggest that this weakening of the association may be due to self-monitoring, where women reduced their emotional eating behavior due to the need to record it on a daily basis. They followed by combining data from both cycles into a mixed-effects model.
The model examined whether emotional consumption differed between active and inactive pill days overall, while adjusting for whether the observation came from the first or second cycle. The results confirmed higher rates of emotional consumption with the use of active versus inactive pills, but at lower levels in the second cycle compared to the first.
Changes in emotional eating behavior were not due to depressed mood, although low mood was observed in relation to active versus inactive pill use. However, the associations were weaker.
In a subgroup with clinically defined binge eating, a similar overall pattern was observed, although the association during the first cycle did not reach statistical significance due to the smaller sample size. Pill type did not change the appearance of weight preoccupation, as expected, as it does not show strong follow-up effects.
These data suggest a specific effect of COCs on EE that is much stronger than that for negative affect and WP.
Hormones can change the brain’s reward pathways for food
Future studies should investigate the mechanisms underlying these associations. The common patterns observed with both endogenous hormones in previous research and exogenous hormones in this study suggest that both may reflect normal rather than abnormal physiology.
Postulated mechanisms include the regulation of dopamine and opioid reward pathways by these hormones. Therefore, COCs may alter reward systems, thereby enhancing liking and consumption of rewards, such as highly palatable foods often consumed during binge eating. Specifically, previous research suggests that COCs may increase liking or craving for such foods, indicating a fertile area for future research.
Given the reduction in emotional consumption across cycles, the role of self-control mechanisms (in which women engage less in this behavior when they have to report their daily consumption patterns) also needs to be validated.
The study only focused on monophasic birth control pills
The researchers did not measure endogenous hormone levels, which may have influenced changes in eating behavior. There was no washout period, which could reduce the differences observed between active and inactive pills. Only monophasic pills were included in this study.
Finally, although each individual serves as their own control, individual genetic and other risk factors could interact with ovarian hormones to determine the ultimate risk of binge eating, as not all women taking COCs exhibit this behavior.
The findings support more personalized contraceptive care
This study suggests that active COC pills are associated with increased emotional eating, which is associated with binge eating. Further research is needed to identify the high-risk group and tailor COC use to each individual.
It is also necessary to identify contraceptives that are less likely to affect emotional eating and the risk of overeating. The potential benefit of training COC users in self-monitoring needs to be validated, as it could improve patient care and reduce the risk of emotional eating.
