Scientists discover same ‘hungry genes' make humans and labradors fat

Independent

07-03-2025

A gene that makes Labradors more likely to overeat is the same gene found in obesity-prone humans, according to new research.
Scientists have discovered that changes to a particular gene, that's responsible for regulating the energy balance in the body, alters the chemical signals that tell our brains we have had enough to eat.
Findings published in the academic journal Science revealed the dog gene found to be most strongly associated with obesity in Labradors is called DENND1B — the same one is also linked with obesity in people.
Researchers at the University of Cambridge analysed the genetics of 250 Labradors and said they have found something 'really powerful' about the biology of obesity risk.
'Owners of slim dogs are not morally superior,' said Dr Eleanor Raffan, who led the study.
'The same is true of slim people. If you have a high genetic risk of obesity, then when there's lots of food available, you're prone to overeating and gaining weight unless you put a huge effort into not doing so,' she added.
The human obesity epidemic is mirrored by an obesity epidemic in dogs. About 40-60 per cent of pet dogs are overweight or obese, which just like humans can lead to a range of health problems.
Dogs are a good model for studying human obesity: they develop obesity through similar environmental influences as humans, and because dogs within any given breed have a high degree of genetic similarity, their genes can be more easily linked to disease.
To get their results, the researchers recruited owners with pet dogs. They measured body fat of the dogs, gave them a 'greediness' score by measuring how much dogs pestered their owners for food and took a saliva sample for DNA.
Dogs carrying the genetic variant most associated with obesity, DENND1B, had around 8 per cent more body fat than those without it.
The researchers then examined whether the genes they identified were relevant to human obesity. They looked at both large population-based studies, and at cohorts of patients with severe, early onset obesity where single genetic changes are suspected to cause the weight gain.
But researchers say there are ways owners can keep their dogs distracted from constant hunger by spreading out each daily food ration.
Scattering food around the garden and using puzzle feeders so it takes longer to eat are some of the suggestions.
Dr Raffan said: 'This work shows how similar dogs are to humans genetically. Studying the dogs meant we had reason to focus on this particular gene, which has led to a big advance in understanding how our own brain controls our eating behaviour and energy use.'
The study found that owners who strictly controlled their dogs' diet and exercise managed to prevent even those with high genetic risk from becoming obese.
Similarly, people at high genetic risk of developing obesity will not necessarily become obese, if they follow a strict diet and exercise regime. But it does mean they are more prone to weight gain.
This discovery adds to the building research of what causes people to overeat. A group of weight loss drugs, such as Ozempic and Wegovy, target some of this biology, but study authors say this study shows something a bit different.
'These genes are not immediately obvious targets for weight-loss drugs, because they control other key biological processes in the body that should not be interfered with. But the results emphasise the importance of fundamental brain pathways in controlling appetite and body weight,' said Alyce McClellan joint first author of the report.