URBANA, ILL. — The University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES) has published the results of a comparison study showing human-grade pet diets could result in “less poop to scoop” for pet owners.

The study, conducted by Kelly Swanson, an endowed professor for the university’s human nutrition department and the division of nutritional sciences at the university, included 12 beagles who were fed four different commercial diets over the course of four weeks.

These four options included a standard extruded kibble diet, a fresh, refrigerated food, and two fresh diets using only USDA-certified human-grade ingredients. The fresh human-grade diets were minimally processed and included ingredients such as beef, chicken, rice, carrots, broccoli, and other small chunks of whole ingredients.

The results of the study concluded that the beagles who consumed fresh diets made from USDA-certified human-grade ingredients excreted up to 66% less fecal matter compared to the beagles fed fresh, refrigerated or kibble diets over the four-week period. The dogs who consumed kibble ate more to maintain their body weight and produced between 1.5 and 2.9 times the poop compared to those who consumed the fresh pet foods.

“This is consistent with a 2019 National Institute of Health study in humans that found people eating a fresh whole food diet consumed on average 500 less calories per day, and reported being more satisfied, than people eating a more processed diet,” Swanson said.

Swanson and her team also found that fresh diets positively impacted the dogs’ microbiomes.

“Because a healthy gut means a healthy mutt, fecal microbial and metabolite profiles are important readouts of diet assessment,” Swanson said. “As we have shown in previous studies, the fecal microbial communities of healthy dogs fed fresh diets were different than those fed kibble. These unique microbial profiles were likely due to differences in diet processing, ingredient source, and the concentration and type of dietary fibers, proteins, and fats that are known to influence what is digested by the dog and what reaches the colon for fermentation.”

Diet did not, however, affect fecal pH or metabolites in these dogs, the study showed.

Swanson had previously conducted a similar study on roosters, which concluded human-grade fresh rooster feed was up to 40% more digestible than extruded feed.

“Based on past research we’ve conducted, I’m not surprised with the results when feeding human-grade compared to an extruded dry diet,” Swanson said. “However, I did not expect to see how well the human-grade fresh food performed, even compared to a fresh commercial processed brand.”

Co-authors of the study are Swanson, two graduate student research assistants — Sungho Do and Thunyaporn Phungviwatnikul — and Maria de Godoy, Ph.D., assistant professor in the University of Illinois’ Animal Sciences Laboratory.

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