I’ve long attributed the onset of my anorexia to the stress of transitioning from elementary to middle school, combined with a personality predisposed to obsessiveness and rigidity. But recently, I was reading a novel where the protagonist offhandedly mentioned that eating disorders in women tend to spike around perimenopause, just as they do around adolescence. A lightbulb went off: These two phases of life are accompanied by massive hormonal upheaval. Could hormones cause eating disorders to develop? The answer, I learned, is a qualified yes.
It’s well-established that eating disorders themselves cause hormonal changes. The prolonged starvation of anorexia can lead to low estrogen and progesterone in women, often accompanied by amenorrhea. Bulimia, too, can cause menstrual dysfunction and mess up levels of sex hormones. Other known hormonal consequences of eating disorders include high cortisol, growth hormone resistance and low insulin, among others.
But, it seems to be a two-way street. Although eating disorders certainly cause hormonal changes, a growing body of research suggests that hormonal changes might, in some cases, trigger eating disorders. “We have good evidence that a range of hormones are relevant to risk and maintenance of eating disorders,” said Pamela Keel, a researcher and professor of psychology at Florida State University.
The correlation is clear. Research shows that eating disorders tends to peak during “critical or sensitive“times of reproductive hormone change. It’s widely known that puberty, when a woman’s reproductive life begins, is a significant period of risk for the development of eating disorders. It’s perhaps a fitting counterpoint, then, that women are also more vulnerable to eating disorders around menopause, when menstruation ends. The hormonal changes of pregnancy, too, can pose a risk: Pregnancy itself presents a ripe opportunity for the onset of binge-eating disorder in some women, while rapid postpartum hormonal changes can trigger delays of other eating disorders.
“Often, periods of hormonal shifts like puberty, pregnancy and menopause are high-risk times for eating disorders to begin or flare up,” said Katherine Hill, vice president of medical affairs at Team, a telehealth platform for eating disorder treatment. According to Keel, this was long explained as a psychological response to bodily changes in the face of a society that exalts thinness above all. Now, she said, “we understand that the same hormones that contribute to changes in body weight and shape impact eating more directly and impact risk for disordered eating.”
Of course, hormones alone can’t cause an eating disorder. (“If that were true, then 100 percent of girls would develop an eating disorder at puberty and 100 percent of women would have binge-eating episodes toward the end of their menstrual cycle,” Keel says.) These diseases emerge out of a complex interplay of factors, including genetics, psychology and environment—but hormones may play a bigger role than previously thought.
Reproductive hormones have been the biggest area of focus, with research-suggesting that estrogen, progesterone and testosterone affect both normal and abnormal food intake.
Animal models also support the idea that these hormones may activate eating disorder behaviors. “There’s growing evidence that gonadal hormones may contribute to the development of an eating disorder and play a role in perpetuating disordered eating,” said Margherita Mascolo, chief medical officer with Alsana, an eating disorder treatment provider. “On a broad level, the research finds that progesterone, which is secreted after ovulation, can lead to bingeing behavior, while estrogen tends to inhibit food intake.” Learning this, I can’t help but wonder my relapse in college was connected to the estrogen-containing birth control I’d just started taking.
Puberty provides a lens to understand how sex hormones might influence eating disorders. We know that some people are more genetically susceptible to developing an eating disorder, but as it turns out, hormonal changes that occur during puberty can influence whether someone’s genetics become their destiny. “Research in twins indicates that the genes that increase risk for eating disorders may be activated in girls during puberty by ovarian hormones,” Keel said. “Hormones trigger expression of a person’s genetic liability of developing an eating disorder, which may be high or low.”
One study showed that heritability of eating disorders in girls was 0 percent before puberty, but more than 50 percent afterward. Boys in the study saw no significant difference, suggesting that female sex hormones are the driver. (In fact, other research has found that testosterone may be protective against eating disorders, perhaps helping to explain why fewer young boys develop eating disorders than young girls.)
A similar interaction between hormones and genetic predisposition unfolds during a woman’s menstrual cycle. According to one studyovarian hormones act like a “master conductor,” turning on and off genetic risk for binge eating; the influence of genes and the rate of binge eating both increase as progesterone surges post-ovulation.
None of this is common knowledge. “In general, physicians get about an hour of education on eating disorders in medical school,” Hill said. “So, unless a physician is particularly savvy about eating disorders, most may not think to warn patients about them at high-risk times throughout their life, like puberty, pregnancy or menopause.”
Eating disorders are common and deadly, so this oversight has real consequences. In an ideal world, Hill said, eating disorder screening would be routine, especially in those undergoing major hormonal transitions. Indeed, Mascolo says, “even though the peak onset is during puberty, eating disorders affect women across their life span.” But because of gaps in medical education and pervasive stereotypes about whom eating disorders affect — namely young, thin, white women — many eating disorders in older women probably go undiagnosed.
There are still a lot of unknowns here, and researchers are quick to point out that more studies are needed to understand the causal relationship between hormones and eating disorders. But what we know so far underscores, once again, the fact that eating disorders are not mere vanity, and they are not all in one’s head; physiology contributes, too.
So, did puberty spark my anorexia in sixth grade? Did birth control pills contribute to my relapse? There is, frustratingly, no definitive answer. In the end, the etiology of eating disorders remains infuriatingly complex. My personality, my environment, society: All of these things certainly contributed. But hormones are tremendously powerful, and even as more research is needed, I feel confident concluding that they played as much of a role in the history of my anorexia as those magazine articles instructing me on how to get thin thighs.