It turns out that between 39 per cent and 59 per cent of pet dogs in Europe, Australia and the US are estimated to be overweight or obese.
In fact, not only humans, obesity is now being considered to be the biggest threat to health and well-being of our pets.
Furthermore, it turns out that certain breeds of dog seem to be more prone to obesity than others, and scientists have found a genetic mutation that seems to make dogs more likely to seek out food.
While genetics certainly seems to be involved, alongside the amount of food and exercise dogs get, one aspect of obesity in dogs that has received little attention to date is the emotional and cognitive aspect.
How motivated different dogs are to access food, and how personality traits such as the response to rewards might play a part now form the basis for a new study published in Royal Society Open Science.
Researchers found that overweight dogs were more likely to choose food containing larger amounts of energy, and more likely to hesitate if they didn't know what kind of reward they were being offered.
This supports the suggestion that dogs could be a promising model for experimentally investigating the emotional and cognitive aspects of obesity in humans.
Scientists have shown that overweight and obese people often record a stronger attraction to energy-rich foods high in fat and sugar than people of healthy weight.
Now, scientists think how one is attracted to these foods is related to how sensitive to rewards they are.
This is seen as a 'personality' trait that differs between individuals and is part of the brain's reward system.
The researchers in the latest study wanted to see if the eating habit of dogs and therefore their weight were related to their sensitivity to rewards in a similar way.
They further studied how eager the dogs were to reach a bowl of food whose energy content was unknown, offering an ambiguous reward.
Using these tasks, the authors concluded that dogs behaved in a similar way to people.
The overweight dogs were more likely to choose the higher-energy reward compared to dogs of an ideal weight, even when it meant ignoring directions given by a person.
The researchers concluded that this showed overweight dogs were indeed more sensitive to rewards.
