Are Some Dogs Hardwired to Overeat?

By Claudia Kawczynska, May 2016

Researchers at Cambridge University looked at Labrador Retrievers (the most popular breed in the U.S. and the UK) to assess why that breed is more prone to obesity than other breeds. Their findings, recently published in the journal Cell Metabolism, point to a possible genetic reason behind this.

“About a quarter of pet Labradors carry this gene [difference],” lead researcher Dr. Eleanor Raffan noted. “Although obesity is the consequence of eating more than you need and more than you burn off in exercise, actually there’s some real hard-wired biology behind our drive to eat,” she added. Labs have the greatest documented obesity prevalence.

More than 300 Labradors, from pets to assistance dogs, were screened for known obesity genes in the study. The international team found that a change in a gene known as POMC was strongly linked with weight, obesity and appetite in both Labradors and Flat-Coated Retrievers.

Other breeds—from the Shih Tzu to the Great Dane—were also screened, but this particular genetic difference was not found.

Dr. Giles Yeo, was one of the human geneticists from the University of Cambridge, who worked on the study. “What we have found is that some Labradors get fat because they have a deletion in a gene within their brain,” he said.

“And this particular gene plays a role in sensing how much fat they have in their body—and so some Labradors don’t know how much fat they have and so keep eating to try to get fatter.”

Researchers also found that the mutation is significantly more common in Labradors selected to become assistance dog breeding stock than those selected to be companions.

It is certainly intriguing why assistance Labs are more prone to be carrying this gene deletion, but as they hypothesized, dogs carrying the POMC deletion may be more likely to be selected as for work as assistance dogs because trainability and temperament are the main “drivers for selection of these dogs, and positive reinforcement with food reward is the mainstay of puppy training.”