Kibble
Extruded dry food is the most studied format by a wide margin. It is complete, affordable, shelf-stable, and convenient. Those are not small things.
The legitimate concern about kibble is what high-heat extrusion does to nutrients. Temperatures above 120°C can reduce the bioavailability of certain vitamins and denature proteins, and some extrusion processes produce Maillard reaction compounds, the result of proteins and sugars reacting under heat, whose long-term effects in pets are not well characterized. A 2024 University of Illinois digestibility study found that extruded diets generally had the lowest macronutrient digestibility compared to frozen raw, freeze-dried raw, and fresh formats tested in the same conditions.
That said, digestibility is not the whole story. Kibble meets AAFCO nutritional standards, has decades of feeding trials behind it, and the dogs eating it are, as a population, doing fine. "Lower digestibility" does not mean "harmful." It means less of what goes in comes out as usable nutrition — a real difference, but a calibrated one.
Raw
Raw meat-based diets have the most passionate advocates and the most genuine risks. On the positive side: a 2024 study published in Frontiers in Veterinary Science comparing 55 dogs on kibble or raw diets for over a year found altered fecal bacterial composition in raw-fed dogs, with some markers suggesting reduced inflammation. A 2023 study found that puppies fed primarily raw food were 29% less likely to develop chronic enteropathy than those on kibble. Raw-fed dogs also consistently show higher digestibility scores in comparative trials.
The problem is pathogens. Raw meat carries real bacterial contamination risk — not just to the animal, but to the humans handling the food and sharing the household. The FDA and most veterinary organizations flag this, particularly for homes with immunocompromised people, young children, or elderly adults. The contamination risk is not theoretical; it has been documented in recalls and case reports.
The other issue is nutritional completeness. Homemade raw diets are frequently unbalanced. Commercial raw products vary widely in quality and standardization. If you feed raw, it matters significantly which product and which formulation.
Fresh (Lightly Cooked)
Fresh, gently cooked food is the newest major format and the least studied, though the research that exists is promising. Mild heat processing — typically 75 to 95°C — is sufficient to kill pathogens without the nutrient losses associated with high-heat extrusion. The 2024 University of Illinois study found fresh and raw formats performed comparably on most digestibility measures, with extruded food trailing both.
The honest caveat is that much of the fresh food research has been funded by fresh food companies, and a recent systematic review in PMC flagged high risk of bias across multiple studies due to industry funding, lack of blinding, and selective reporting. The signal is real; the magnitude is uncertain.
Fresh food is also expensive. For many owners, the cost is prohibitive as a primary diet, though mixing fresh food with kibble is increasingly supported in the literature as a reasonable middle path.
What the research actually supports
No format has long-term controlled trials showing clear survival or longevity benefits. What the evidence does support, fairly consistently, is that less processing correlates with higher digestibility, and that raw and fresh formats show favorable microbiome and inflammatory markers compared to extruded diets in short-to-medium term studies. It does not support the conclusion that kibble is dangerous, or that raw is worth the pathogen risk for every household, or that premium pricing reliably predicts nutritional quality.
The most defensible reading of the current literature: a high-quality kibble is a reasonable baseline; adding fresh whole food where budget allows is supported; raw feeding requires careful sourcing and household risk assessment; and any diet, in any format, can be done badly.
Your veterinarian and the ingredient label matter more than the category.
Sources include Geary et al., Translational Animal Science (2024); Hiney et al., Frontiers in Veterinary Science (2024); and a systematic review of fresh pet food claims, PMC/Animals (2025). This article is general education, not individualized dietary advice.
■ Filed under Nutrition. Corrections: corrections@proactivepethealth.com