Switching your dog to a raw diet does change the gut microbiome, often within days, but that shift alone doesn’t prove your dog will be healthier for it. Studies show real changes in bacterial populations and metabolic markers, yet researchers still can’t draw a straight line from those changes to better long-term health. What matters more for your decision is food safety and complete nutrition, and that’s where the real differences between products show up.
TL;DR:
- Changing a dog’s microbiome through raw feeding is rapid but often temporary, with early shifts in bacteria fading within a month without lasting health benefits.
- Most studies on raw diets are observational with small sample sizes, showing associations rather than proven clinical improvements like longer lifespan or fewer allergies.
- Raw diets commonly increase bacteria that ferment proteins and fats, but the impact on overall health depends on gut balance and diet consistency rather than specific bacteria changes.
- The main risks of raw diets include bacterial contamination such as Salmonella or Listeria, which pose safety concerns for households, especially with vulnerable populations.
- Formulation quality and pathogen testing are more important than raw labeling; well-made freeze-dried options offer safer, nutritionally complete alternatives for interested owners.
Table of Contents
- What the science shows: key studies and what they actually prove
- Which gut bacteria shift and what that shift actually means
- What health markers actually moved in the research
- Pathogen risks: what public health agencies actually found
- Why formulation quality matters more than the raw label
- How to choose and transition to a safer raw or freeze-dried food
- Where Loyal Saints Pets fits into the evidence
- Balancing curiosity about the microbiome with real-world caution
- Freeze-dried nutrition built around what the research actually supports
- Sources
- FAQ
What the science shows: key studies and what they actually prove
If you’ve read that raw feeding “restores your dog’s natural gut,” the actual research tells a more careful story. A 2021 study switching dogs from kibble to a raw diet modeled after wolf feeding found that the microbiome responded fast. Researchers followed 6 dogs and 6 wolves, sampling stool at days 1, 7, 14, 21, and 28. Fusobacteria and Bacteroidetes rose early in the dogs switched to raw, moving their gut communities closer to the wolves’ baseline. But here’s the part that often gets left out of raw-feeding pitches: many of those changes were transient. By day 28, the dogs’ microbiomes had only partially converged toward the wolf pattern, and some early shifts faded.
That matters because a fast change in bacterial populations doesn’t tell you whether your dog is better off. It tells you the gut community is responding to new inputs, which is exactly what you’d expect from any major diet change, raw or not.
A larger, more recent study adds nuance rather than resolution. The 2024 Frontiers cohort study compared 27 dogs fed kibble to 28 dogs fed a raw meat-based diet, all clinically healthy and already eating their respective diets long-term. The researchers found significant differences in species diversity and in the fecal metabolome, along with higher local immune markers in the raw-fed group. That sounds promising until you consider the study design: these dogs weren’t randomly assigned to a diet and tracked from day one. They were pre-existing groups with different feeding histories, ages, and possibly different owners’ management styles. When a study observes two already-different populations rather than randomizing dogs into groups, it can show association, not causation.
A 2025 systematic review in MDPI Animals looked across the available raw-feeding literature and found the same pattern repeating: inconsistent diversity findings and few studies that measure actual clinical outcomes like allergy rates, weight stability, or lifespan. The review’s conclusion was blunt: owner-reported health improvements from raw feeding generally lack strong scientific backing.
A few terms are worth knowing so you can judge these claims yourself:
- Randomized studies assign subjects to a diet group by chance, which controls for hidden differences between groups.
- Crossover studies have the same dogs eat each diet in sequence, so each dog serves as its own control.
- Observational studies compare groups that already differ (like dogs whose owners chose raw versus kibble), which can reveal patterns but not prove what caused them.
Most of the raw-feeding research sits in the second and third categories, with small sample sizes. That’s not a reason to dismiss it, but it is a reason to read “raw diets change the microbiome” and “raw diets improve health” as two very different claims.
Which gut bacteria shift and what that shift actually means
Across several studies, a consistent group of bacterial taxa moves when dogs switch to raw feeding. Knowing which ones, and what they do, help you interpret headlines more skeptically.
- Fusobacteria and Bacteroidetes tend to increase on raw diets, both linked to protein and fat fermentation.
- Firmicutes often shifts in relative abundance depending on carbohydrate content, since many Firmicutes species specialize in fermenting fiber and starch.
- Erysipelotrichaceae, Catenibacterium, and Clostridiaceae show diet-associated changes in several cohort comparisons, though direction and magnitude vary by study.
A 2021 controlled feeding trial found measurable shifts in Fusobacteria and Bacteroidetes within the first week of switching dogs to a raw diet, based on stool sampling starting at day 1, though the same study found many of these changes softened by day 28. That’s a meaningful data point for anyone expecting an instant, permanent transformation.
The functional story behind these names matters more than the names themselves. A gut community shifted toward Fusobacteria and Bacteroidetes generally handles protein and fat fermentation differently than one dominated by carbohydrate-fermenting Firmicutes species. That changes the mix of short-chain fatty acids and amino-acid byproducts your dog’s colon produces. Some of those byproducts feed colon cells and support gut lining health. Others, in excess, are linked to different digestive outcomes. The same bacterial genus can behave differently depending on what it’s fed and what other microbes surround it, so a taxa list alone doesn’t tell you whether the shift is good, neutral, or something to watch.
Timing is the other piece owners underestimate. Microbiome changes after a diet switch can start within 24 hours, driven by the immediate change in available nutrients rather than a wholesale replacement of bacterial species. Whether those early changes stabilize into a lasting new normal or partially reverse, as seen in the 2021 wolf-comparison study, seems to depend on how long the new diet continues and how consistent it is.
What health markers actually moved in the research
Bacterial population shifts are one measurement. Whether your dog’s actual health improves is a separate question, and the research on that front is more limited than marketing copy suggests.
- The 2024 Frontiers cohort study found 63 serum metabolites differed between kibble-fed and raw-fed dogs, along with higher fecal immunoglobulin A, immunoglobulin G, and intestinal alkaline phosphatase in the raw-fed group.
- The same study found no consistent difference in systemic inflammation markers like C-reactive protein between the two groups.
- Metabolome differences tracked closely with the macronutrient makeup of each diet (protein and fat ratios) rather than with the “raw” label itself.
That last point deserves attention. A 2021 crossover feeding study that varied protein and fiber content directly found that diet composition drove microbiome responses more than whether the food was labeled raw or cooked. In other words, some of what gets attributed to “raw magic” may really be a function of higher protein content, lower carbohydrate load, or different fat ratios, all of which a well-formulated cooked or freeze-dried diet can also deliver.
Put together, the current evidence shows real, measurable biochemical differences between raw-fed and kibble-fed dogs. It does not show that those differences translate into fewer allergies, longer lifespans, or fewer vet visits. Local gut immune markers moving upward is interesting and worth more research, but it isn’t the same as a proven clinical benefit.
Pathogen risks: what public health agencies actually found
This is the section that gets glossed over in raw-feeding enthusiasm, and it shouldn’t be.
- An FDA Center for Veterinary Medicine survey of 196 raw pet food samples collected between 2010 and 2012 found Salmonella in 15 samples and Listeria monocytogenes in 32 samples, concluding raw pet food was more likely to carry disease-causing bacteria than other food types tested.
- A separate microbiological study found Salmonella or Listeria monocytogenes in 15 of 42 raw meat-based diets tested, roughly 35.7%, and matching pathogens in about one-third of fecal samples from raw-fed dogs.
- That same study found genetically linked Salmonella isolates in both the food and the feces within the same households, and detected no pathogens in tested extruded (kibble-type) foods or in feces from dogs eating them.
The FDA’s survey found Listeria monocytogenes in a notable portion of raw pet food samples tested, a rate that led the agency to caution owners directly on its pet food safety page. The CDC takes a similarly direct position: it recommends against feeding raw pet food or treats to dogs and cats, because uncooked animal protein can carry Salmonella and Listeria that spread through a household, not just to your dog. The CDC also advises asking manufacturers directly about final-product pathogen testing before you buy.
Households with young children, elderly residents, pregnant people, or anyone immunocompromised carry higher stakes if a pathogen makes it from bowl to countertop to hand. Basic controls cut that risk substantially: separate cutting boards and utensils for raw pet food, immediate handwashing after handling, sanitizing food-prep surfaces with a diluted bleach solution or an equivalent disinfectant, and never letting raw food sit out at room temperature. Our detailed breakdown of raw dog food and salmonella risk walks through the handling steps in more depth.
Why formulation quality matters more than the raw label
Here’s where a lot of raw-feeding conversations go wrong: they focus entirely on “raw versus cooked” and skip past the bigger question of whether the diet is nutritionally complete at all.
- Homemade raw diets frequently fall short on calcium, phosphorus balance, vitamin D, and essential fatty acids unless they’re formulated by a veterinary nutritionist.
- Whole or ground bones included for calcium can cause tooth fractures, GI obstruction, or perforation if the bone type or preparation is wrong for the dog’s size and chewing style.
- Diets built around a single protein without organ meat, fat, or produce variety can create calorie imbalances that show up as weight gain or nutrient deficiency long before any microbiome change becomes relevant.
The WSAVA Global Nutrition Committee has been direct about this, warning that raw meat-based diets carry documented risks including bacterial and parasitic contamination, nutritional inadequacy, and bone-related injury, and recommending against feeding them for these reasons. That’s a stronger stance than most owners realize when they start researching raw feeding.
Pro Tip: Ask any raw or freeze-dried brand whether their formula is tested to meet AAFCO’s complete-and-balanced standard for your dog’s life stage, and get the answer in writing before you buy.
If your dog is on a long-term raw diet, whether homemade or commercial, periodic veterinary bloodwork can catch nutrient imbalances before they become clinical problems. Our guide to veterinarian-approved pet diets covers what that oversight should look like in practice.
How to choose and transition to a safer raw or freeze-dried food
Once you’ve decided raw or freeze-dried feeding fits your household, the practical work is in vetting the product and introducing it carefully.
- Ask the manufacturer whether they run final-lot pathogen testing for Salmonella and Listeria, not just facility-level spot checks.
- Ask what pathogen-control method they use, such as high-pressure processing, and confirm the formula was reviewed for AAFCO completeness by a qualified formulator.
- At home, store raw or freeze-dried food separately from human food prep areas, use dedicated bowls and utensils, and wash hands and surfaces immediately after handling.
- Dispose of any leftover raw food promptly rather than leaving it out, and never let your dog “finish it later” from a bowl sitting at room temperature.
- Transition gradually over 5 to 7 days, mixing increasing amounts of the new food with the old, and track stool consistency and appetite daily.
Pro Tip: If your dog develops loose stool, vomiting, or reduced appetite that lasts beyond 72 hours after a diet change, stop the new food and call your veterinarian rather than pushing through it.
Freeze-dried products deserve one clarifying note: freeze-drying removes moisture, but it is not a sterilization step. A product can be freeze-dried and still carry pathogens if the raw material wasn’t tested and treated properly beforehand, which is exactly why the manufacturer questions above matter more than the packaging claim. Our safety checklist for raw dog food and our comparison of micronutrients in raw versus freeze-dried formats go deeper on this distinction.
Where Loyal Saints Pets fits into the evidence
The company offers freeze-dried options including chicken and beef products, made from human-grade, whole ingredients, without fillers or synthetic additives.
The company states its formulas meet AAFCO’s complete-and-balanced standard and have veterinarian approval, emphasizing nutritional completeness and professional review. That said, “AAFCO-complete” and “vet-approved” are claims worth confirming directly with any manufacturer, including this one, alongside their specific pathogen-testing practices for the lot you’re buying. Shelf-stable freeze-drying removes the thawing, fridge space, and ice-pack logistics that can make some feeding routines challenging to sustain.
Balancing curiosity about the microbiome with real-world caution
The microbiome research is genuinely interesting, and it’s reasonable to be curious about how diet reshapes your dog’s gut. But curiosity shouldn’t outrun caution. The strongest evidence right now points to safety and complete formulation as the decisions that actually protect your dog, not the presence or absence of the word “raw” on the bag.
If you’re considering a diet change, a conversation with your veterinarian or a veterinary nutritionist beats guesswork every time, especially for puppies, seniors, or dogs with existing health conditions. Vetted freeze-dried options can be a reasonable middle ground for owners who want raw-style nutrition without DIY formulation risk, but homemade raw diets built without professional guidance carry real, documented downsides.
— Kristina
Freeze-dried nutrition built around what the research actually supports
You’ve just read what the science does and doesn’t say about raw feeding, and the honest answer is that safety and complete formulation matter more than the raw label itself. That’s exactly what Loyal Saints Pets built its freeze-dried line around.
- Freeze Dried Raw Chicken, 14oz, made from human-grade chicken with no fillers or synthetic additives.
- Freeze Dried Raw Chicken, 5oz, a smaller size suited to trial runs or smaller dogs.
- Freeze Dried Raw Beef, 14oz, formulated to the same AAFCO-complete standard.
All three are shelf-stable, so there’s no fridge space, thawing, or ice packs to manage. The formulas are stated to be AAFCO-complete and veterinarian approved; confirming current pathogen-testing details with the manufacturer is recommended before purchase. You can browse the full Beef, Chicken, and Turkey + Salmon lineup, or join the Halo Club membership for recurring savings and free shipping on future orders.
This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.
Sources
- Fecal microbiota composition, serum metabolomics, and markers of inflammation in dogs fed a raw meat-based diet compared to those on a kibble diet
- Get the Facts! Raw Pet Food Diets can be Dangerous to You and Your Pet | FDA
- About Pet Food Safety | Healthy Pets, Healthy People | CDC
FAQ
How do I fix my dog’s gut microbiome?
The most evidence-backed approach is feeding a complete and balanced diet consistently, since diet composition drives most microbiome changes more than any single “fix.” Talk to your veterinarian before adding probiotics or making major diet changes, especially if your dog has ongoing digestive symptoms.
What is the 80-10-10 rule for raw dog food?
It is not an AAFCO or veterinary nutrition standard, and WSAVA’s Global Nutrition Committee warns that home-formulated raw diets built on ratio rules alone often miss key nutrients.
What are the downsides of feeding a dog raw diet?
The documented downsides include pathogen contamination, with Salmonella or Listeria found in 35.7% of raw diets tested in one study, plus nutritional gaps and bone-related injury risk in poorly formulated homemade recipes. The CDC recommends against raw feeding for many households specifically because of these zoonotic and safety concerns.
What kills gut bacteria in dogs?
Antibiotics are the most common cause of significant gut bacteria loss in dogs, along with certain illnesses and sudden diet changes that disrupt the existing bacterial balance. Rebuilding a stable microbiome afterward generally takes consistent, complete nutrition over time rather than a single dietary switch.
