Your Birth Control Pill May Be Affecting Your Eating Behavior

A new study published in JAMA Network Open is raising important questions about a side effect of combined oral contraceptives that has largely gone unexamined: the potential link between birth control pills and binge eating. For the millions of women who use oral contraceptives and have noticed changes in their eating behaviors, the findings offer a scientific framework for something many may have sensed but have never been able to explain.

What the Study Examined

Investigators recruited 422 women from the Michigan State University Twin Registry already using monophasic combined oral contraceptives, meaning birth control pills that deliver the same dose of hormones throughout the active pill cycle. Participants completed daily surveys over 49 consecutive days across two pill pack cycles, reporting on their eating behaviors and emotional states on days when they were taking active hormone pills versus inactive pills, also known as placebo or sugar pills.

“Because we tracked the same women day to day, we could see how eating changed with hormone exposure,” said co-investigator Shaunna Clark, Ph.D., an associate professor of psychiatry and behavioral sciences at Texas A&M University’s Naresh K. Vashisht College of Medicine.

The outcome the team focused on was emotional eating, a measure that captures the tendency to eat in response to emotions rather than hunger, which is closely associated with binge eating behavior. They also tracked weight preoccupation and negative affect, meaning mood and emotional distress, to understand whether any changes in eating behavior were driven by hormonal effects directly or simply by mood changes.

What They Found

Women showed significantly increased emotional eating on days when they were taking active hormone pills compared with inactive pills, and this pattern held across both cycles of the study, suggesting it was consistent and not a fluke. Crucially, the increases in emotional eating were not explained by changes in mood or negative affect, meaning the hormonal influence on eating behavior appeared to be operating independently of how women were feeling emotionally.

The findings also held among the subset of 51 women in the study who met clinical criteria for binge eating episodes, suggesting the association is relevant not just for everyday overeating but for more significant eating disorder behavior as well.

To rule out a broader hormonal influence on all eating-related thoughts, investigators also tracked weight preoccupation, which did not change based on pill type. That specificity strengthens the case that the effect is real and targeted rather than a general hormonal mood effect.

Why This Matters

The biological reasoning behind the finding is grounded in what researchers already know about endogenous, meaning naturally occurring, ovarian hormones. Studies have previously shown that the period after ovulation, when both estrogen and progesterone are elevated simultaneously, is associated with the highest risk for binge eating in women. Combined oral contraceptives mimic exactly that hormonal environment during the active pill phase, essentially recreating the hormonal conditions most closely linked to risk of binge eating every single month.

Approximately 82% of women in the United States use combined oral contraceptives at some point in their lives, making this a public health question of significant scale.

What to Do With This Information

This is an early study, and the investigators are clear that more work is needed to understand which women are most affected and what alternative contraceptive options might carry a lower risk. The findings suggest that if you have noticed changes in your eating behavior since starting oral contraceptives, that observation is worth bringing up with your health care provider. There may be contraceptive options better suited to your individual health profile, and having that conversation is an important step in personalized care.

“Findings like these can help us better understand how different hormone exposures affect eating behavior,” Clark said. “Over time, that could help clinicians and patients make more informed decisions about care.”