Explained: Why your Lab is always hungry

Dogs love food. Some love it more than others, and some of those are Labrador retrievers — the bottomless pits of the canine world. Scientists announced recently that they’ve found a gene variant in Labs that may explain that constant state of “Please Feed Me.” The findings were published in the journal Cell Metabolism.

Dog obesity isn’t something we talk about a lot, but there sure is a lot of it. In the US and other wealthy countries, between 34 and 59 per cent of dogs are overweight. And yes, fat dogs are cute, but they’re also in danger of some serious health problems. Canine obesity can cause heart disease, strain on a dog’s joints, diabetes, and can even shorten a dog’s lifespan.

Some breeds, like black Labs, chocolate Labs, and Golden Retrievers, are more obesity-prone than others. This is likely because, like many of us, they are highly motivated by food. Labs’ human companions learn quickly that a treat is the trick to getting their dog to behave. But those treats add up.

Research-ers recruited nearly 400 adult Labrador participants. Some of the dogs were fat, while others were not, but all of them were healthy, with no pre-existing conditions.

As relatives, of course, the Labs had a great deal of genetic material in common with each other and with other dog breeds. But they also had one gene variant that stood out: the deletion of 14 base pairs from a gene called pro-opiomelanocortin, or POMC. Previous studies of this POMC variant have shown a relationship with appetite and a feeling of fullness.

Each dog could have one copy of the POMC variant, two copies, or none. The more copies a dog had, the fatter and more food-motivated it was. And about 23 per cent of labs are carrying at least one copy of the variant.

“People who live with Labradors often say they are obsessed by food, and that would fit with what we know about this genetic change,” Cambridge University metabolism expert and lead author Eleanor Raffan said in a press statement.

Her co-author, Stephen O’Rahilly of the Wellcome Trust-Medical Research Council Institute of Science, says these findings have implications beyond kibble. “Common genetic variants affecting the POMC gene are associated with human body weight and there are even some rare obese people who lack a very similar part of the POMC gene to the one that is missing in the dogs.