Golfer Lee Trevino once said, “A hungry dog hunts best.” Recent research suggests that hunger might actually not be the best way to improve a dog’s performance.

Holly Miller, PhD, a researcher from the University of Kentucky, designed a study with colleague Charlotte Bender to test how well dogs functioned when they were hungry versus when they had recently eaten. The study specifically focused on observing the dogs’ search accuracy, memory, and self-control in different stages of hunger.

Miller said one of her main reasons for undertaking the study was to determine if food could be used to propel dogs to higher performance levels.

“I had conducted some previous research on self-control depletion in dogs and I was interested in knowing how to enhance canine performance,” Miller said. “As a dog trainer, I was also interested in whether the advice to withhold all food from dogs prior to training was appropriate.”

The results of their study published in Behavioural Processes revealed that a hungry dog isn’t always the top dog when it comes to performance.

Study setup

Miller and Bender recruited 14 dogs including nine females and five males, and ranging in age from one to 10 years old, to perform two specific tasks while under observation.

The dogs were separated into two groups: one group that was fed 30 minutes before testing, and one that ate 90 minutes beforehand. Each group was tested both in a fasted state and after having eaten at their specified time.

The first task tested the dogs’ self-control by requiring each dog to sit in a room alone, where they had to sit and stay for 10 minutes without getting up. The dogs then went straight to the second activity, a search task, where they were required to remember where treats were located among a group of containers. The search task was intended to assess the dogs’ working memory when hungry and when fed.

The primary purpose of conducting the two tasks concurrently, according to researchers, was because it has been shown that behavioral inhibition completed before a search task is “known to reduce persistence and search accuracy in food restricted dogs.”

Surprising results

According to researchers, dogs that had eaten 30 minutes before the search task were 73.3 percent correct in the search task, compared to 64.2 percent when they were in a fasted state. There wasn’t a significant difference between the dogs that searched in a fasted state and 90 minutes after eating, with accuracy scores of 64.8 percent and 65.2 percent, respectively.

“I thought it was very interesting that dogs searched more accurately for food when they were less hungry. That seemed almost paradoxical on some levels,” Miller said.

Researchers explained their results by writing, “The results suggest that memory for the location of a food reward, as assessed by accurate searches on a visible displacement task, was significantly better when the dogs were tested 30 minutes following the consumption of a meal than when tested in a fasted state. This enhancement was time limited; when dogs were tested 90 minutes after breakfast, their performance was not better than when tested in a fasted state.”

Miller and Bender made sure to note that while they interpreted the results as indicating that glucose boosted search results, the difference between fasted and fed dogs may also be at least partly due to motivation. They quoted previous studies finding that increased motivation results in increased performance up to a certain point, until it begins to result in a decline in performance.

Real-world implications

The results of Miller’s study may have implications for researchers, trainers, and pet owners.

Researchers commonly operate under the assumption that animals perform better when hungry because the possibility of obtaining food motivates them, according to the published report. The study results go against that assumption because it appears at the dogs showed better memory and search accuracy 30 minutes after eating.

The study also speculates that dogs’ feeding schedule can be modified to optimize their performance. According to the researchers, many trainers feed dogs once daily at the end of the day, but a better approach might be to feed them breakfast and then distribute additional food or snacks to keep their blood glucose levels consistently high throughout the day.

Miller said the study results can be interpreted to provide practical advice for anyone who wants a better-performing dog.

“I would say that if your dog has a difficult time controlling his behavior when he is hungry, giving him food might help increase his self-control,” she said.

Study details

Miller, H.C., Bender, C., The breakfast effect: Dogs (Canis familiaris) search more accurately when they are less hungry. Behav. Process. (2012). View the study abstract