In 2021, the FDA announced that they had approved Wegovy, a GLP-1 receptor agonist, as a treatment for chronic weight management. Since then, it feels like every pharmaceutical company has jumped at any opportunity to push their own GLP-1 drug for weight loss or weight management. In turn, use of these medications has skyrocketed. Recent reports suggest that as of 2022, 12% of adults in the United States have taken a GLP-1 agonist for weight loss at some point.
These medications are widely viewed as a win for people struggling with weight loss. However, many are also concerned about their long-term physical and mental effects, particularly for people with eating disorders.
To properly discuss these concerns, it’s important to first understand how GLP-1 drugs actually work.
GLP-1 is a naturally occurring hormone that influences our blood sugar levels, insulin levels, and feelings of hunger. The GLP in GLP-1 stands for glucagon-like peptide. “Glucagon-like” refers to the fact that the structure of GLP-1 resembles that of glucagon, a hormone involved in regulating blood sugar.
The effects of GLP-1s on the body are caused by GLP-1 molecules binding with GLP-1 receptors. Receptors are proteins that sit in the membrane of cells and bind a specific molecule. This molecule could be a hormone, neurotransmitter, or another protein. When a molecule binds to a receptor, the receptor typically undergoes a change in shape that can lead to a variety of different biological responses in the cell. Scientists call anything that can bind to the receptor and cause the changes that create biological responses an agonist.
Caption: The before and after process of natural and synthetic GLP-1 binding to GLP-1 receptors. Pink circles represent naturally occurring GLP-1 hormones and green circles represent man-made GLP-1 receptor agonists. Black circle added to the green indicates that these synthetic agonists have been slightly modified. The GLP-1 receptor undergoes a shape change during binding which leads to different biological responses. Illustration by Donnisa Edmonds.
GLP-1 is the naturally occurring agonist for GLP-1 receptors.
Weight loss drugs, like Wegovy and Ozempic, are synthetic copies of GLP-1 that have been modified slightly. These drugs are called GLP-1 receptor agonists because they can bind to GLP-1 receptors and produce the same effects as the naturally occurring GLP-1 hormone.
The GLP-1 receptor agonists in these drugs bind receptors in our gut and brain.
In our gut, this binding increases insulin levels and reduces blood sugar levels. It also helps delay a process known as gastric emptying, which refers to the time it takes for food to move through your stomach and leave it empty. When gastric emptying is delayed, people tend to feel full for longer because it takes longer for food to leave their stomachs.
In the brain, GLP-1 agonists reduce signalling and activity in the parts of the brain that make food rewarding and tell us that we’re hungry. They also increase activity in brain regions that tell us that we’re full.
These changes to our brain activity and gut processes reduce people’s feelings of hunger and their desire to seek out food, which in turn promotes weight loss.
Caption: GLP-1 (pink) and GLP-1 receptor (green) binding in the gut and in the brain produce different biological responses that lead to weight loss. Illustration by Donnisa Edmonds.
Eating disorders exist on a wide-spectrum, but most are at least partially characterized by some form of food restriction. For people who deal with restrictive eating, the goal of eating disorder treatment is usually to return to normal eating habits and shift focus away from weight loss.
However, as we discussed earlier, GLP-1 medications turn down the volume of the cues from your brain and gut that tell you that you’re hungry and should seek out food. For people with eating disorders who are already restricting their food intake, this effect of GLP-1 medications could worsen behavior. For people in recovery from eating disorders, these medications could disrupt treatment progress and lead to relapse.
On a broader societal level, the use of GLP-1 medications for weight loss may be reinforcing the negative stigmas around fatness and being overweight that often contribute to the development of eating disorders.
The majority of research on GLP-1 receptor agonists and eating disorders has been done in people with binge eating disorders. The results from these studies are largely positive. GLP-1 agonists have been shown to reduce binge-eating episodes, abnormal eating patterns, weight, and BMI (though BMI is a very flawed metric!). Most studies do also report a wide range of negative side effects including nausea and vomiting. It is also important to note that most of these studies focus on short-term effects that may not hold up with extended use.
Currently, there is little to no research on how GLP-1 medication impacts other eating disorders. We know next to nothing about how these drugs may be impacting people with higher levels of food restriction, which is risky considering how common these medications are and how easy it is to access them.
However, there is one study that looked at the relationship between body image and interest in GLP-1 medications. This study reports that people who are more interested in GLP-1 medications and more willing to tolerate its negative side effects have higher levels of body dissatisfaction and shame, more bias against fat people, and more disordered eating behaviors.
While this study doesn’t specifically look at eating disorders, it does suggest that people with eating disorders may be more likely to seek out GLP-1 medications.
Overall, weight loss associated with GLP-1 medications is often a result of the drug reducing the mental and physical cues that tell people to eat. This effect is exactly what makes these medications potentially dangerous for people with eating disorders.
It’s clear that we need more research evaluating the impact of these drugs on eating disorders outside of binge-eating disorders, but this could take a long time. Until then, it will be important for clinicians and doctors to screen for these disorders before prescribing these medications. Screening will be particularly important for people who are considered overweight, since their restrictive or disordered eating habits are already often overlooked because their weight doesn’t reflect the “typical” look of the disorder. We can also all integrate more forms of eating disorder prevention in our daily lives, including: changing the way we talk about others appearances, shifting our language around food and dieting, and educating ourselves on fatphobia and fat stigma. Linked below are a few resources to learn more about eating disorders, eating disorder prevention, and fatphobia.
Resources:
https://www.nationaleatingdisorders.org/
https://www.maintenancephase.com/
www.allianceforeatingdisorders.com/eating-disorder-support-groups-and-programs/
https://www.barnesandnoble.com/w/reclaiming-the-black-body-alishia-mccullough/1145412536
https://www.npr.org/2020/07/20/893006538/fat-phobia-and-its-racist-past-and-present
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