Genes Behind Obesity Discovered in Dogs — and Humans
Scientists have identified obesity-related genes in dogs that are also linked to weight gain in humans, shedding new light on why some individuals—both canine and human—struggle to maintain a healthy weight.
A team from Cambridge University, studying Labrador retrievers, found that a gene called DENND1B plays a key role in regulating appetite and body weight. This gene affects the brain’s leptin-melanocortin pathway, crucial for energy balance and hunger control. Four additional genes with smaller effects were also mapped, all sharing links to human obesity genetics.
“The results emphasize how fundamental brain pathways control appetite and body weight,” said Alyce McClellan, co-author of the study. However, she noted that these genes likely aren’t immediate targets for weight-loss drugs because they influence many other vital processes in the body.
Researchers also observed behavior in dogs that mirrored human tendencies. Dogs with high genetic risk of obesity showed greater food motivation and were less picky eaters. “We found that dogs at high genetic risk were much more interested in food — the same pattern we see in people with a high genetic risk of obesity,” said Natalie Wallis, another co-author.
Despite these genetic challenges, dogs whose owners carefully controlled diet and exercise stayed at healthy weights, showing that environment and management can overcome genetic predisposition — a hopeful message for humans too.
Importantly, no single gene determines obesity risk. Rather, a combination of multiple genes influences whether a dog—or a person—is prone to gain weight. “Our study shows that if you have high genetic risk, and food is abundant, you’ll likely overeat unless you put serious effort into avoiding it,” explained Dr. Eleanor Raffan, study leader.
By studying dogs, scientists were able to separate the dog’s natural food motivation from owner-imposed controls, which is harder to isolate in human studies. This has provided clearer insights into how genetics shape eating behavior.
The study also highlights a growing problem: between 40% and 60% of pet dogs are overweight or obese, mirroring global human obesity rates and leading to serious health issues for pets.
To identify the obesity genes, researchers gathered DNA samples from dogs, measured body fat, and assessed “greediness” scores. Dogs with the DENND1B variant had about 8% more body fat than those without it.
Owners can help manage their dogs’ weight by spreading out meals using puzzle feeders, scattering food in the garden for foraging, or choosing more filling diets.
Dogs, the researchers say, are a “good model” for human obesity because they share both genetic and environmental factors influencing weight gain. “This work shows how genetically similar dogs are to humans,” said Dr. Raffan, adding that the findings mark “a big advance in understanding how our brains control eating behavior and energy use.”
The study, published in Science, opens new doors to understanding obesity and highlights that with effort, even genetically at-risk individuals—human or canine—can maintain a healthy weight.