Some creatures are simply built for hunger. Scientists studying British Labradors have unearthed a handful of genes that crank up appetite and pack on extra pounds. The twist? These same genes lurk in human DNA, quietly nudging some people toward an unshakable obsession with food.
The primary culprit is a gene called DENND1B. In Labradors, it shows up like an overeager dinner guest, driving an insatiable hunger. Humans have it too—and, unsurprisingly, those with certain variations of the gene are more likely to struggle with obesity.
DENND1B doesn’t just make dogs beg at the table; it directly interferes with the leptin melanocortin pathway, a brain circuit responsible for balancing energy intake. When this system is out of tune, appetite regulation becomes a losing battle. In short: the body keeps demanding calories, whether it needs them or not.
Researchers also identified four other obesity-linked genes with smaller—but still significant—effects. Each one mapped directly onto human DNA, reinforcing the reality that weight gain is more than just a matter of willpower. The genetics of appetite are woven deep into biology.
The study didn’t just look at lab samples—it observed real-life Labradors in action. Dogs with high-risk obesity genes weren’t just heavier; they were also far more food-obsessed. They begged more, scavenged more, and generally behaved like furry little food addicts.
“These genes aren’t simple on-off switches. They’re tangled up with other crucial biological processes, making them tricky targets for weight-loss drugs,” explained Alyce McClellan of Cambridge’s Department of Physiology, Development and Neuroscience. “But they highlight just how much appetite control is wired into the brain.”
Owners who micromanaged their dogs’ diets and exercise routines managed to keep even genetically predisposed dogs at a healthy weight. But it took discipline—lots of it. The same principle holds for humans: genetic risk isn’t destiny, but it does mean staying slim requires a whole lot more effort.
Dr. Eleanor Raffan, who led the study, had a sharp takeaway: “Owners of slimmer dogs aren’t morally superior. Just like thinner people aren’t inherently better at ‘self-control.’ If your genes push you toward overconsumption, staying slim in a food-rich world requires relentless vigilance.”
By studying Labradors, scientists could isolate genetic appetite from environmental factors. Human studies get messy—after all, people control their own food intake. But in dogs, researchers could track the difference between a genetically ravenous pet and an owner’s ability to regulate its diet.
The research, published in *Science*, reinforces what many already suspect: weight isn’t purely about willpower. For some, resisting extra calories is like trying to fight a software glitch hardwired into the brain. And unless someone rewrites that genetic code, the craving never really shuts off.
Five Fast Facts
- Labradors were originally bred as working dogs, and their food obsession may stem from their history as fishermen’s helpers, always rewarded with scraps.
- The leptin melanocortin pathway, crucial for appetite control, is also involved in regulating mood and stress responses.
- DENND1B has been previously linked to asthma, suggesting it may influence multiple biological systems beyond hunger.
- Some dog breeds, like Greyhounds, have naturally low body fat and wouldn’t gain weight easily—even with unlimited food.
- Cambridge scientists previously discovered that an obesity-related mutation in Labradors is more common in assistance dogs, possibly because food motivation makes them easier to train.