For decades, eating disorders have been framed primarily as psychological conditions tied to weight and body image. But a new study from the Karolinska Institutet in Stockholm suggests the biological reality is far more nuanced, with distinct genetic signatures for different disorders that are not simply about how much a person weighs.
The research, published in Nature Mental Health, analyzed genetic data from nearly 40,000 individuals with binge-eating behavior and about 25,000 with anorexia nervosa, comparing them against a control group of more than 1.2 million people without eating disorders. The team identified six genetic markers linked to binge eating and eight associated with anorexia, two of which had never been previously reported.
“Our findings show that eating disorders are not just about body weight. Many of the genetic variants associated with these conditions differ from the variants that influence how much a person weighs,” said Lu Yi, principal researcher at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet. “This provides a more nuanced picture for the biological basis of eating disorders.”
Distinct biological pathways
The study found that the genetic factors influencing binge eating and anorexia are largely separate from those that affect body mass index (BMI), even though weight is a central feature of both conditions. This suggests that eating disorders cannot be reduced to metabolic or weight-related explanations alone.
“The study demonstrates that different eating disorders are partly driven by distinct biological mechanisms,” said Lisa Dinkler, assistant professor at Karolinska Institutet. “In the long term, this knowledge may contribute to more targeted treatment strategies that take into account the specific characteristics of each condition.”
For binge eating, some of the identified markers overlap with those linked to impulse-control behaviors such as smoking, risk-taking, higher BMI, and attention-deficit hyperactivity disorder (ADHD). Anorexia markers, by contrast, showed stronger genetic connections to obsessive-compulsive disorder (OCD).
These findings align with a broader understanding of mental health conditions as having shared genetic vulnerabilities. The researchers caution, however, that the markers are still weak predictors on their own and must be combined with other risk factors to assess an individual's likelihood of developing an eating disorder.
Eating disorders affect millions of people worldwide, with Western Europe consistently reporting the highest burden among high-income regions. The conditions typically emerge early, with an estimated 95% of first-time cases occurring by age 25, and can lead to significant health damage, distress, and impaired functioning.
The study's authors hope that by clarifying the genetic architecture of these disorders, clinicians can eventually move toward more personalized approaches. As Dinkler put it, “Different eating disorders are partly driven by distinct biological mechanisms,” which could pave the way for treatments that address the specific biology of each condition rather than treating them all under a single umbrella.
While the research is still in its early stages, it adds to a growing body of evidence that eating disorders are complex medical conditions with roots in genetics, neurobiology, and environment—not merely lifestyle choices or societal pressures. For the millions affected across Europe, this shift in understanding could eventually translate into better prevention and care.
