Slim chance of defying genetic odds in the weight game

Staying thin may not be the result of sheer willpower. A new study shows that maintaining a healthy weight can come down to genetics.


imageBROKER / Alamy Stock Photo

A recent study on 2,000 healthy, thin participants reveals that 74 percent of thin participants had a family history of being thin and healthy, concluding that thin people have a genetic tendency to keep the weight off.  

“There is a combination of genetic variants that makes you more likely to be really obese, and a combination of those same variants that makes you more likely to be really thin,” says Fernando Riveros-McKay, one of the lead authors of the research, which was conducted by researchers from the Wellcome-MRC Institute of Metabolic Science and the University of Cambridge.  

While previous research has shown many connections to obesity and genetics, little was known about the genetic relationship between thinness and any hereditary predisposition. The researchers sought to find hereditary explanations to healthy individuals who are resistant to obesity in environments that would otherwise tend to cause it, publishing the results of the largest cohort study of its kind to date in the journal PLOS-Genetics.  

“Some people are just luckier in the genetic lottery. and that makes it easier for them to keep a low body mass index (BMI). And some are unluckier and have a harder time losing weight,” says Riveros-McKay.  

The research can give insight for future studies to eventually reach a possible treatment for obesity, a leading cause of non-infectious diseases worldwide among children. “More studies on the functional aspects of the genetic influences on both extremes of the BMI distribution need to be done before we start thinking about treatments. We still don't know the way most of these genetic variants influence obesity or thinness,” explains Riveros-McKay.  

The researchers compared obese participants with healthy, thin individuals with a BMI lower than 18. Thin participants were examined to ensure they were healthy and had no eating disorders or any other diseases causing their thinness. They had to have been thin for most of their lives.  

Extensive research has been done on obesity and thin individuals with eating disorders, but no study of this size has been conducted on healthy, thin individuals who remain thin in obesity-inducing environments.  

According to the study, the results obtained have encouraged the researchers to continue studying and gathering information on “the biology underlying human energy homeostasis, and as an alternative approach to uncovering potential anti-obesity targets for drug development.” 


  1. Riveros-McKay, F. et al. Genetic architecture of human thinness compared to severe obesity. PLOS-Genetics 15, 1 (2019).

     | article

Read this next

MAT Deficiency: Wider effects of a rare disease

A case of a rare childhood disease reveals a new mutation as underlying cause and  identifies unknown manifestations of the disease on the skin and hair.

Searching for answers surrounding autism

Replicating a gene linked to autism in a monkey model could shed light on its underpinnings.

An instigator for immunodeficiency

A genomic survey of immunodeficient patients reveals a gene with an important role in fending off infection and controlling inflammation