Obesity genes that cause both dogs and humans to gain excessive weight have been identified in a groundbreaking study.
Researchers from the University of Cambridge, while studying Labrador retrievers, discovered several genes associated with canine obesity. Their findings have significant implications for human health, as the same genes were found to be linked to obesity in people.
The primary gene identified in this study is DENND1B, which plays a crucial role in the brain’s leptin melanocortin pathway. This pathway is responsible for regulating energy balance in the body, affecting how much food an individual consumes and how efficiently energy is stored.
Additional Genetic Factors and Their Role in Obesity
Beyond DENND1B, researchers identified four additional genes linked to obesity in dogs. These genes, although exerting a smaller effect than DENND1B, were found to have direct parallels in the human genome. Their presence emphasizes the role of fundamental brain pathways in controlling appetite and body weight.
“The results emphasize the importance of fundamental brain pathways in controlling appetite and body weight,” explained Alyce McClellan, from Cambridge’s Department of Physiology, Development, and Neuroscience, who co-authored the study.
“(But) 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.”
Behavioral Differences in Dogs with High Genetic Risk
To further understand how these genes influence behavior, the research team observed how frequently dogs pestered their owners for food and whether they exhibited picky eating habits. Their observations revealed that dogs with a higher genetic predisposition to obesity displayed a greater interest in food.
“We found that dogs at high genetic risk of obesity were more interested in food,” said Cambridge co-author Natalie Wallis.
“Dogs at high genetic risk of obesity showed signs of having higher appetite—as has also been shown for people at high genetic risk of obesity.”
This finding supports previous research suggesting that genetic predisposition to obesity in humans often correlates with increased appetite and a tendency to overeat.
The Role of Diet and Exercise in Managing Obesity
Despite genetic predispositions, the study found that obesity is not an unavoidable fate. Owners who strictly controlled their dogs’ diets and ensured regular exercise successfully prevented obesity, even in dogs with a high genetic risk. However, maintaining a healthy weight required significantly more effort and vigilance for these dogs than for those without the obesity-linked genes.
Similarly, people with a high genetic risk for obesity are not doomed to gain weight, but they must adhere to a stricter diet and exercise regimen to maintain a healthy body mass.
Understanding the Influence of Multiple Genetic Factors
As with human obesity, no single gene determines whether a dog will become overweight. Instead, multiple genetic variants contribute to a dog’s overall risk, with their combined effects determining whether they are more or less prone to excessive weight gain.
Study leader Dr. Eleanor Raffan highlighted the study’s implications, saying, “Studying the dogs showed us something really powerful (and the same is true of 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 further explained, “By studying dogs we could measure their desire for food separately to the control owners exerted over their dog’s diet and exercise. In human studies, it’s harder to study how genetically-driven appetite requires greater willpower to remain slim, as both are affecting the one person.”
The Canine Obesity Epidemic and Its Parallels in Humans
The findings of this study are particularly relevant given the rising rates of obesity in both humans and dogs. Today, between 40% and 60% of pet dogs are classified as overweight or obese, mirroring the ongoing obesity epidemic in humans. Obesity in dogs can lead to serious health complications, including diabetes, joint issues, and a shortened lifespan.
To conduct their research, scientists recruited dog owners and assessed their pets’ body fat, appetite tendencies, and genetic profiles. They collected saliva samples for DNA analysis and compared the genetic data to the dogs’ obesity status.
Their results confirmed that dogs carrying the DENND1B genetic variant had, on average, 8% more body fat than those without the gene.
Practical Tips for Managing Canine Obesity
While the genetic factors identified in the study influence a dog’s appetite, owners can take steps to mitigate excessive weight gain. Researchers suggest strategies such as using puzzle feeders, spreading food out around the yard to slow down eating, and providing nutrient-dense meals that promote satiety.
By keeping dogs engaged and making mealtimes more interactive, owners can help their pets manage hunger and maintain a healthy weight.
Dogs as a Model for Understanding Human Obesity
The researchers emphasized that dogs serve as an excellent model for studying human obesity because they share similar environmental influences with their owners. Additionally, specific dog breeds maintain a high degree of genetic similarity, making them valuable for controlled genetic studies.
“This work shows how similar dogs are to humans genetically,” says Dr. Raffan, who believes the study represents “a big advance in understanding how our own brain controls our eating behavior and energy use.”
As obesity continues to be a major global health concern, research into genetic factors affecting weight gain provides valuable insights. By studying both human and canine obesity, scientists hope to develop more effective strategies for managing weight and improving overall health in both species.