Ever wondered why some dogs seem naturally rotund, no matter how much they run around? Turns out, the same genes that contribute to obesity in humans are also found in our pooches.
In a new genome study, scientists have pinpointed several genes linked to obesity in dogs—genes that we humans share, too. This means our favourite furry friends (sorry, cats) could actually help researchers unlock new insights into weight gain, health, and complex diseases.
Though environmental factors such as the cheap availability of ultra-processed foods are commonly singled out for rising rates of obesity, scientists emphasise that it’s a complex condition with a multitude of biological root causes. A big factor is heritability, with a 2007 study estimating that a person has between a 40 to 70 per cent chance of developing obesity due to the genes they inherit from their parents.
As Dr Eleanor Raffan, lead academic on the new research, told BBC Science Focus, “If you are unlucky enough to get genes that make you prone to obesity, that manifests as greater appetite, making it harder to resist those drives to overeat. Slim people aren’t morally superior – they just don’t need to exert as much willpower to keep at a healthy weight.”
To see if obesity was also hereditary in dogs, researcher Natalie Wallis and her team looked at the genes of 241 pet Labrador retrievers – a particularly obesity-prone dog breed.
Using a cross-species approach, they identified multiple obesity-contributing genes that dogs and humans share. Among these, the gene DENND1B – which plays a key role in how our cells process energy – emerged as a particularly strong genetic link between human and canine obesity.
“By looking in just a few hundred Labrador retrievers, we have uncovered new biology of relevance across species. I hope more people consider using the canine genetic model for more scientific discovery in the future, especially for complex disease,” Wallis told BBC Science Focus.
As well as offering scientists a new model to understand human disease, this research could also help us take better care of our dogs. Pet obesity is on the rise, with The Royal Veterinary College in London recently reporting that 1 in 14 dogs are recorded as overweight in the UK each year.
In the US, a 2022 Association for Pet Obesity (APOP) survey found that 59 per cent of dogs were overweight, indicating a widespread problem within pet health. However, until now the genetic basis of canine obesity hasn’t been widely studied.
Understanding a pet’s genetics could be a game-changer for their care. “Our results underscore the importance of encouraging exercise and limiting food intake for our pet dogs," says Dr Raffan. "Importantly, our data shows that management is most important in dogs with the highest genetic risk, and therefore greatest appetite.”
“Many people still blame owners of fat dogs, saying they are lazy or indulgent, and the same stereotypes are mirrored about people with obesity. Our data shows it is much harder work to control food intake in the dogs with high risk. That should change how we address canine obesity in practice: we need to target owners of high-risk dogs and offer them support on effective management (rather than blaming them).”
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