Evolution Tells Us to "Eat Up"
Eating disorders can be brought on by genes and hormones in women’s bodies.
Posted Oct 05, 2015
It seems cruel to think about, but are our bodies aiding us in developing an eating disorder? Unfortunately, the answer for some women, is yes. These disorders can manifest themselves in many forms and can even be brought on by genes and hormones in women’s bodies.
At certain times during the month, women are at a greater risk for experiencing eating disorder symptoms. This is due to varying hormone levels—namely estrogen and progesterone—that are present in a woman’s body across the menstrual cycle.
Biologically, in the post-ovulation phase, it appears that women’s bodies are telling them to “eat up” to prepare for possible pregnancy. These signals are all part of a natural, evolutionary process.
However, that natural process can increase eating disorder symptoms. Culturally, when our bodies tell us to “eat up,” we’re telling ourselves that any weight we gain is a bad thing, even when it is driven by evolution and supposed to happen. When women do eat more during their monthly cycle—appeasing biological urges to eat —they still worry about the effects on body weight and shape. It’s a no-win situation.
Our research found that hormone variations across the cycle can impact not only our desire to eat, but our desire to engage in emotional eating (the tendency to overeat in response to negative emotions) and binge eat. These increases can leave women vulnerable to other types of eating disorder behaviors and cognitions, especially women with poorer body images.
This cycle forces women into a tough situation: give in to the biological urges to eat, and possibly feel bad later, or go against these urges, and leave yourself feeling deprived and vulnerable to future overeating episodes.
This potentially dangerous chain of events can trigger obsessive weight concerns and more emotional eating and even binge eating, which can be five times higher during the high-risk phase of the menstrual cycle. Binge eating can then lead to eating disorders, such as anorexia nervosa and bulimia nervosa, that have significant medical consequences and the highest mortality rates of any psychiatric disorder.
The main question is why and how do these hormones trigger risk? The answer again seems to lie in our bodies or, more specifically, in our genes. We have known for quite some time that eating disorders run in families and that there are genetic factors that increase the chances that some women will develop the disorders. However, there is new data suggesting that genetic risk factors likely also increase the chances that some women will respond to hormonal changes with eating disorder symptoms. In fact, the influence of genes on emotional eating and binge eating nearly doubles during high-risk hormonal phases, suggesting that increases in genetic risk underlie the cycle-eating disorder symptom associations observed in earlier studies.
Regardless of the level of genetic risk, however, there is good news. Just knowing that natural changes in hormones can lead to increased urges to engage in eating disorder symptoms can help women plan for urges rather than being surprised and overwhelmed by them. Doctors can time their prevention and treatment efforts around these naturally occurring events and help patients develop coping skills to decrease urges. But the first step in this process is recognizing the need for treatment and accessing care.
Moving forward, it is imperative that people understand that eating disorders are multiply caused disorders that deserve to receive the same level of attention, treatment resources, and funding as other disorders.
Only when we are able to “level the playing field” in this way will we be able to make significant strides in decreasing the intense suffering and disability that can be associated with eating disorders.