Overweight Dogs and People May Respond Similarly to Food
Dogs and their owners have a lot in common — probably more than you realize. Sure, some dogs look and behave like their owners (and vice versa). After all, people tend to choose dogs with personalities similar to their own, and dogs have learned to recognize human emotions and adjust their behavior in response to them.
People and pooches also share a common “growing” problem: excess weight and obesity. Nearly 71 percent of U.S. adults are considered overweight or obese (body mass index [BMI] of 25 or higher), while an estimated 56 percent of U.S. dogs are considered overweight or obese (body condition score [BCS] of 6 or higher on a 9-point scale).
But the similarities between overweight dogs and people don’t stop there.
Researchers at Eötvös Loránd University in Budapest, Hungary, have found the behavior of overweight dogs is similar to some personality traits of overweight humans. The scientists observed how normal weight and overweight pet dogs behaved during two experiments in which food motivation played an important role. (We’ve all met at least one very food-motivated dog, right?)
In the first experiment, researchers tested dogs’ willingness to follow a nonverbal signal to choose a particular bowl containing a low-incentive treat (a piece of carrot or orange) when a second bowl contained either a high-incentive treat (a higher-calorie, meat-based treat) or no treat at all. The bowls were deep enough that dogs couldn’t see what was inside until they were close to the chosen bowl. Dogs were divided into two groups, depending on the contents of the second bowl, and the researcher always indicated the bowl containing the low-incentive (aka healthy, low-calorie) treat. The placement of the bowls was switched somewhat randomly.
What researchers found was, regardless of weight (or body condition), dogs were more likely to complete the experiment when the alternative dish contained the high-incentive treat. The dogs also chose faster towards the end of the test, compared to dogs in the group that had to choose between the healthy treat or no treat at all. However, dogs’ body weight did affect how often they chose the indicated bowl. Overweight dogs were less likely to follow the researcher’s direction to a specific dish when the alternative bowl contained a reward.
In the second experiment, one side of the room was designated as the rewarded location and the other side was the non-rewarded location. In the training phase of the experiment, only one bowl was placed: either at the rewarded location, where the dish always contained a high-incentive treat, or at the non-rewarded location, where the bowl was always empty. For the trial, a bowl was placed on the ground either in the rewarded or non-rewarded location in semi-random order. Once placed, the researcher went behind the dog owner and touched his or her shoulder to indicate the dog could be released. After release, the dog had up to 30 seconds to reach the bowl.
During the test phase of this second experiment, one bowl was placed in the rewarded or non-rewarded location in random order. But then the researcher placed the bowl in an ambiguous location, halfway between the rewarded and non-rewarded locations.
As any dog owner would expect, dogs were more likely to go to the bowl at the rewarded location than the non-rewarded one before the 30 seconds were up regardless of their body weight or condition. However, compared to normal-weight dogs, overweight dogs were less likely to check out the bowl when it was placed in the ambiguous location.
Interestingly, overweight dogs were selective in their responses to food. Compared to normal-weight dogs, the overweight dogs in this study were more sensitive to the presence of a high-incentive reward treat, even if it meant ignoring directions to a specific bowl. Overweight dogs were also less eager to approach the bowl in an ambiguous location than normal-weight dogs.
The study results demonstrated that normal and overweight dogs behave differently in tasks involving food rewards and human interaction, with overweight dogs trying to maximize the intake of higher-quality food. While food choices made by overweight and obese people are complex, research shows they tend to be attracted to energy-dense foods. As a result, the researchers concluded that the dogs’ responses were similar to what might be expected in normal and overweight people, and that dogs are a promising model for investigating obesity in humans.
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