An international team led by King’s College London published the largest genetic study of anorexia nervosa to date on August 19, 2026, in Nature Mental Health, and reported that the genetics of eating disorders is mostly not the genetics of body weight. Pooling 27 global datasets, the researchers found eight DNA regions linked to anorexia nervosa and six linked to binge eating in people of European ancestry, and found that the two conditions relate to body size genetics in opposite directions.
Key takeaways
- Anorexia and binge eating share genetic overlap with psychiatric disorders, but their genetic links to body size run in opposite directions.
- Most of the genetic signal for both conditions was not shared with BMI, so these are not simply weight genes.
- Fourteen DNA regions across more than 63,000 cases explains a small slice of risk, so nothing about diagnosis changes because of this paper.
What the study found
The work came from the Eating Disorders Working Group of the Psychiatric Genomics Consortium. According to the paper in Nature Mental Health, the binge-eating analysis compared 39,279 people with binge-eating behavior against 1,227,436 people without it, and the anorexia analysis compared 24,223 people with anorexia against 1,243,971 controls. All of the main analyses were in people of European ancestry, and cases were overwhelmingly female (96% in the binge-eating analysis, 94% in the anorexia analysis).
Six DNA regions were linked to binge eating. Eight were linked to anorexia, six of them confirming regions found in a 2019 study and two identified for the first time.
The two conditions are related but not the same. Their genetic correlation was 0.46, meaning they share a moderate amount of genetic risk rather than most of it, and the odds that this overlap is coincidence are far below 1 in 1,000 (P = 3.44 x 10^-30).
The headline result is the split. Both conditions showed similar positive genetic correlations with psychiatric disorders, but opposing genetic correlations with body size traits. The authors write that “most of the genetic signal in BE and AN was not shared with body mass index.”
The researchers also studied binge eating as a symptom rather than as a diagnosis, since it shows up in binge-eating disorder, bulimia nervosa, and some cases of anorexia. Some binge-eating regions had already been tied to body size, including one near FTO, the best-known obesity gene.
Dr. Kumar’s take
Opposite directions is the finding that matters. It argues against the two folk models that still shape how these conditions get handled: that anorexia is dieting taken too far, and that binge eating is obesity with guilt attached. If either were true, the genetics would track BMI. It does not. Both conditions carry their own genetic architecture that sits closer to psychiatric illness than to body weight, and pointing at the scale to explain them misses the biology.
That fits the metabolic picture from earlier anorexia genetics, where the paper notes a positive genetic correlation with HDL cholesterol and negative correlations with insulin resistance, leptin, and type 2 diabetes, all independent of BMI. Anorexia looks metabolically distinct, not just underfed.
Now the limits. Fourteen regions across more than 63,000 cases is a thin map. Common genetic variation explained about 13% of the risk of anorexia and about 5% of binge eating, and the individual regions account for a small fraction of even that. This is a study about what causes these illnesses at the population level, not a test anyone can take.
The ancestry problem is real too. The main results come from people of European ancestry, and the team says future work will expand to other populations. A finding that only holds in one ancestry group is not yet a finding about humans.
What it means for you
Nothing here changes a diagnosis, a treatment, or a screening test in the next year. There is no gene panel for eating disorders and this study does not create one.
What it does change is blame. If you or someone in your family has anorexia or a binge-eating pattern, the biology behind it is not a weight problem and it is not a willpower problem. It sits alongside other psychiatric conditions, and it deserves the same kind of care.
That also means general weight advice is the wrong tool here. Approaches that help with ordinary weight management, like eating the same meals every day or time-restricted eating, are aimed at a different problem, and applying them to a suspected eating disorder can make things worse. If restriction, bingeing, or purging is part of the picture, that belongs with a clinician who treats eating disorders, not with a diet plan.