All Natural Dog Food: The Science Behind What Your Dog Actually Needs
Explore the canine science behind all natural dog food — how dogs digest whole foods, evolutionary diet biology, and what research says about natural diets.
Defining "Natural" in Dog Food: What the Science Actually Says
The term "natural" in pet food has a specific regulatory definition. According to the U.S. Food and Drug Administration, a pet food labeled "natural" must consist of ingredients from plant, animal, or mined sources that have not been produced by or subjected to a chemically synthetic process. However, this definition permits certain processing methods — cooking, extrusion, drying, and fermentation — that fundamentally alter the food's structure.
This matters because many owners assume "all natural dog food" means raw, unprocessed, or identical to what a wild canid would eat. The scientific reality is far more nuanced. The Association of American Feed Control Officials (AAFCO) allows the "natural" label on kibble that has been cooked at temperatures exceeding 300°F (149°C), as long as the original ingredients were not synthetically derived. Vitamins and minerals added to meet nutritional standards must be declared, and their synthetic nature must be disclosed — yet the overall product can still carry the natural label with a disclaimer.
From a nutritional science perspective, the processing method matters as much as the ingredient source. A study published in the Journal of Animal Science found that extrusion cooking — the standard process for making kibble — increases starch gelatinization, which actually improves digestibility for dogs. This means that a well-formulated kibble with natural ingredients may deliver more usable nutrition than a raw diet with identical ingredients.
The Evolutionary Biology of the Canine Diet
This evolutionary finding fundamentally challenges the popular notion that dogs should eat exclusively like wolves. While dogs share approximately 99.9% of their mitochondrial DNA with gray wolves, the genes under strongest selection pressure during domestication were precisely those related to dietary flexibility. Dogs that could thrive on the starchy scraps and agricultural byproducts of early human settlements survived and reproduced. This is convergent evolution with humans — we both adapted to agricultural diets, though through different genetic mechanisms.
The physiological implications are significant:
- Starch digestion: Dogs can efficiently digest cooked starches, extracting glucose from carbohydrates at rates comparable to omnivorous mammals. Wolves cannot do this efficiently.
- Gut microbiome adaptation: Research from the Merck Veterinary Manual indicates that dogs have gut microbial populations adapted to ferment both animal proteins and plant fibers, producing short-chain fatty acids (SCFAs) that support colon health.
- Dental structure: While dogs retain carnassial teeth designed for shearing meat, their molars have adapted for crushing and grinding — a trait less developed in wolves.
- Intestinal length: Dogs have proportionally longer small intestines than wolves relative to body size, providing more surface area for nutrient absorption from mixed diets.
Physiological Mechanisms: How Dogs Process Natural vs. Processed Foods
The physiological processing of "all natural" ingredients versus synthetically supplemented foods reveals some counterintuitive findings:
Bioavailability differences: A 2020 study in the British Journal of Nutrition compared nutrient absorption in dogs fed whole-food-based diets versus diets with synthetic vitamin premixes. The results showed that certain fat-soluble vitamins (A, D, E, K) from whole food sources had 15–22% higher bioavailability than their synthetic counterparts. However, certain minerals like zinc and iron were actually more bioavailable in chelated synthetic forms. This means that the "best" diet isn't purely natural or purely synthetic — it's a strategic combination.
Gut transit time: Whole-food diets with intact fiber matrices typically result in gut transit times of 12–18 hours in dogs, compared to 8–12 hours for highly processed kibble. Longer transit time allows more complete fermentation of prebiotic fibers in the colon, producing beneficial SCFAs like butyrate, propionate, and acetate. These compounds nourish colonocytes, modulate immune function, and may reduce inflammation.
Glycemic response: The glycemic index of dog foods varies dramatically based on processing. Whole grains like barley and oats in minimally processed forms produce lower postprandial glucose spikes than the same grains extruded into kibble. For dogs predisposed to insulin resistance or diabetes (notably breeds like Samoyeds, Cairn Terriers, and Keeshonds), this distinction has clinical relevance.
| Nutrient Category | Whole Food Source | Processed/Synthetic Equivalent | Canine Digestibility Difference |
|---|---|---|---|
| Protein | Fresh chicken muscle meat | Chicken meal (rendered) | Fresh: ~92% digestible; Meal: ~85% digestible |
| Carbohydrates | Whole cooked sweet potato | Extruded sweet potato kibble | Whole: moderate glycemic; Extruded: high glycemic |
| Fat | Salmon oil (cold-pressed) | Animal fat (sprayed on kibble) | Cold-pressed: higher omega-3 retention; Sprayed: oxidation risk |
| Vitamin E | Sunflower seeds, spinach | DL-alpha-tocopheryl acetate (synthetic) | Natural (d-alpha): ~2x bioactivity vs. synthetic (dl-alpha) |
| Calcium | Bone (ground) | Calcium carbonate supplement | Bone: ~65% absorption; Carbonate: ~50% absorption (with food) |
Breed Variations in Dietary Adaptation
Not all dogs are equally adapted to the same dietary patterns. Research into breed-specific genomics reveals meaningful differences in how breeds metabolize different macronutrient ratios, which has direct implications for choosing an all natural dog food.
High-starch adapted breeds: Agricultural companion breeds like the Shih Tzu, Pekingese, and Bichon Frise tend to carry higher copy numbers of AMY2B. These breeds have been associated with human agricultural societies for thousands of years and typically tolerate grain-inclusive natural diets well. Their risk of diet-related obesity is higher when fed calorie-dense natural diets without portion control.
Low-starch adapted breeds: Arctic and working breeds — including Siberian Huskies, Alaskan Malamutes, and Greenland Dogs — carry fewer AMY2B copies, closer to the wolf baseline. A 2015 study in Genome Research found that these breeds maintained a more carnivorous metabolic profile. For these dogs, all natural diets with higher protein ratios (35–45% protein on a dry matter basis) and lower starch content (below 25% DM) may be more physiologically appropriate.
Breeds with specific sensitivities:
- German Shepherds: Higher prevalence of exocrine pancreatic insufficiency (EPI) and food-responsive enteropathy. May benefit from novel-protein natural diets (venison, rabbit, duck) rather than common proteins like chicken or beef.
- Irish Setters: Known gluten-sensitive enteropathy (a heritable condition). Must avoid wheat, barley, and rye — even in "natural" formulations.
- Soft-Coated Wheaten Terriers: Predisposed to protein-losing enteropathy. Require carefully managed protein sources, often requiring hydrolyzed or single-source novel proteins.
- Boxers: Higher rates of inflammatory bowel disease (IBD) and food allergies. Often benefit from limited-ingredient natural diets with omega-3 supplementation.
Common Misconceptions About All Natural Dog Food
| Common Myth | What the Science Shows | Verdict |
|---|---|---|
| "Dogs should eat like wolves — all meat, no grains." | Dogs diverged from wolves 20,000–40,000 years ago and evolved AMY2B gene copies specifically for starch digestion. They are facultative omnivores, not obligate carnivores. | ❌ Myth |
| "Grain-free natural food is healthier for all dogs." | The FDA has investigated a link between grain-free diets (specifically those high in peas, lentils, and potatoes) and dilated cardiomyopathy (DCM) in dogs. Grains are not inherently harmful and provide valuable nutrients. | ❌ Myth |
| "Natural preservatives are always safer than synthetic ones." | Mixed tocopherols (vitamin E) and rosemary extract are effective natural preservatives, but they have shorter shelf-stability than BHA/BHT. Rancid fats from inadequate preservation are more dangerous than approved synthetic preservatives at regulated levels. | ⚠️ Partially True |
| "Raw natural diets are the most biologically appropriate." | The AVMA discourages raw feeding due to pathogen risk (Salmonella, Listeria, E. coli) to both pets and humans. Cooking increases protein and starch digestibility. | ❌ Myth |
| "If the ingredients are natural, the food is automatically balanced." | An all-chicken-and-rice diet is "natural" but severely deficient in calcium, vitamin A, vitamin D, taurine, and multiple trace minerals. Nutritional balance requires formulation, not just ingredient quality. | ✅ Fact (the myth is wrong) |
| "Dogs can't digest plant matter." | Dogs produce cellulase via gut microbiota fermentation and have adapted to extract significant nutrition from cooked vegetables, grains, and legumes. Plant matter provides essential prebiotic fiber. | ❌ Myth |
What the Research Says: Key Studies on Natural Diets for Dogs
1. Axelsson et al. (2013) — Nature: "The genomic signature of dog domestication reveals adaptation to a starch-rich diet." This foundational study identified 36 genomic regions showing signs of positive selection during domestication, with starch metabolism genes (AMY2B, MGAM, SGLT1) among the strongest signals. This proved dogs are genetically adapted to omnivorous diets.
2. FDA Grain-Free/DCM Investigation (2018–ongoing): The FDA received reports of DCM in dogs eating grain-free diets containing high proportions of peas, lentils, chickpeas, and potatoes. While causation has not been definitively proven, the investigation highlighted that "natural" grain-free formulations using legume-heavy recipes may carry cardiac risks, potentially related to taurine interference or other unknown mechanisms.
3. Bermingham et al. (2017) — Journal of Animal Science: Examined digestibility of raw vs. cooked diets in dogs. Found that cooking increased protein digestibility by 8–12% and starch digestibility by 30–40% compared to raw equivalents. Raw diets also showed higher fecal bacterial shedding, including potential pathogens.
4. Le Bourquin et al. (2022) — Frontiers in Veterinary Science: Compared gut microbiome diversity in dogs fed commercial kibble vs. whole-food-based diets. Dogs on whole-food diets showed higher microbial diversity and increased populations of Faecalibacterium prausnitzii, a beneficial bacterium associated with anti-inflammatory effects. However, the whole-food diets required careful supplementation to meet AAFCO standards.
Practical Implications: Choosing and Feeding All Natural Dog Food
What this science means for your daily feeding decisions:
1. Check the AAFCO statement first. Regardless of how "natural" the marketing looks, the food must carry an AAFCO statement of nutritional adequacy for your dog's life stage (growth, adult maintenance, or all life stages). This is non-negotiable. A natural food without AAFCO certification is an unbalanced food.
2. Evaluate the protein-to-starch ratio for your breed. Arctic and working breeds (Huskies, Malamutes, Belgian Malinois) generally benefit from higher-protein natural diets (≥30% protein on a dry matter basis). Companion breeds (Cavaliers, Pugs, Shih Tzus) do well with moderate protein (22–28% DM) and can efficiently utilize grain-inclusive formulations.
3. Understand preservation trade-offs. Natural foods preserved with mixed tocopherols and rosemary extract have shorter shelf lives — typically 6–9 months unopened vs. 12–18 months for synthetically preserved kibble. Buy smaller bags that your dog can finish within 3–4 weeks of opening to minimize fat oxidation.
4. Transition gradually over 7–10 days. Mix 25% new food with 75% old food for days 1–3, then 50/50 for days 4–6, then 75/25 for days 7–9, then 100% new food by day 10. This allows the gut microbiome to adapt, reducing diarrhea and gas.
5. Budget realistically. Premium all natural dog foods typically cost $1.50–$3.50 per pound, compared to $0.80–$1.50 per pound for standard commercial kibble. For a 50 lb (23 kg) dog eating approximately 2.5 cups daily, expect to spend $60–$120 per month on a high-quality natural diet.
6. Consider a hybrid approach. Many veterinary nutritionists recommend a high-quality AAFCO-certified kibble as the nutritional base (providing guaranteed complete nutrition), supplemented with fresh natural toppers — cooked eggs, plain yogurt, steamed vegetables, or cooked lean meats — at no more than 10% of total daily caloric intake.
When Diet Choices Might Signal or Cause Problems
While choosing an all natural diet is generally a personal preference that can work well, certain situations warrant veterinary consultation before making dietary changes:
- Chronic gastrointestinal signs: Recurrent diarrhea, vomiting, or weight loss lasting more than 3 days may indicate IBD, EPI, or food-responsive enteropathy that requires specific therapeutic diets — not just "natural" ingredients.
- Known food allergies or sensitivities: True food allergies affect an estimated 1–2% of dogs with allergic skin disease. Diagnosis requires a strict 8–12 week elimination diet trial using a novel or hydrolyzed protein, which may or may not be "natural."
- Kidney disease (CKD): Dogs with chronic kidney disease need carefully controlled phosphorus and protein levels. Many natural foods are high in phosphorus from bone content and organ meats, which can accelerate CKD progression.
- Heart disease or DCM risk: If your dog is a breed predisposed to DCM (Doberman Pinschers, Great Danes, Golden Retrievers, Boxers) or is currently eating a grain-free diet with legumes as primary carbohydrates, discuss taurine levels and cardiac screening with your vet.
- Pancreatitis history: High-fat natural diets (those with visible fat content, rich organ meats, or added oils) can trigger pancreatitis flare-ups. Dogs with pancreatitis history need diets with less than 18% fat on a dry matter basis.
- Growth stage (puppies under 12 months): Puppies have precise calcium-to-phosphorus ratio requirements (1.1:1 to 1.4:1). Homemade or improperly formulated natural diets frequently cause developmental orthopedic diseases in growing puppies.
Always consult your veterinarian before transitioning to a new diet, especially for dogs with existing health conditions. Your vet can recommend appropriate formulations and may refer you to a board-certified veterinary nutritionist (ACVN diplomate) for custom diet formulation.
Frequently Asked Questions
Why do dogs digest starches better than wolves?
Dogs carry multiple copies of the AMY2B gene (ranging from 4 to 30 copies depending on breed), which produces pancreatic amylase — the enzyme that breaks down starch into maltose. Wolves carry only 2 copies. This genetic adaptation occurred during domestication as dogs co-evolved with humans in agricultural settlements where starchy food scraps were a primary food source. Dogs also have adapted MGAM and SGLT1 genes for further carbohydrate processing and glucose absorption. This is why an all natural dog food with whole grains like brown rice or oats can be perfectly appropriate for most breeds.
Can dogs thrive on a purely plant-based natural diet?
While dogs are facultative omnivores and can extract nutrition from plant sources, a purely plant-based diet requires extremely careful formulation to meet all amino acid requirements — particularly taurine, L-carnitine, and the correct balance of essential amino acids. The AVMA and most veterinary nutritionists advise against fully vegan diets for dogs without direct oversight from a board-certified veterinary nutritionist. Deficiencies in taurine and L-carnitine have been linked to dilated cardiomyopathy. If you're considering a plant-forward natural diet, keep animal protein at a minimum of 40–50% of total protein content.
How do dogs process natural preservatives versus synthetic ones?
Dogs metabolize both natural and synthetic preservatives through hepatic (liver) detoxification pathways. Natural preservatives like mixed tocopherols (vitamin E) and ascorbic acid (vitamin C) are processed as nutrients — the body recognizes and utilizes them. Synthetic preservatives like BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene) are metabolized by cytochrome P450 enzymes and excreted. At FDA-approved concentrations, both types are considered safe. However, natural preservatives degrade faster, meaning the fats in natural-preserved foods may oxidize before the "best by" date if storage conditions are poor. Oxidized fats cause gastrointestinal upset and long-term inflammatory damage.
What does it mean when my dog prefers processed treats over natural foods?
This is a palatability response driven by fat coating and flavor enhancers. Most commercial treats — natural or otherwise — are sprayed with animal fat digest or coated with palatability enhancers (often listed as "natural flavors") that trigger dogs' fat and umami taste receptors. Dogs have approximately 1,700 taste buds (compared to humans' 9,000), but their fat-detection sensitivity is extremely high. A dog preferring processed treats isn't signaling that the food is "better" nutritionally — it's responding to concentrated fat and flavor compounds. You can improve natural food palatability by warming it to body temperature (101–102.5°F / 38.3–39.2°C), adding warm water or low-sodium bone broth, or mixing in a small amount of canned natural food as a topper.
Is grain-free natural dog food the same as all natural dog food?
No. "Grain-free" and "all natural" are separate labeling claims. A food can be grain-free but contain synthetic additives, artificial preservatives, and rendered ingredients — making it not "natural." Conversely, a food can be all natural and include whole grains like brown rice, barley, or oats. The grain-free trend has come under scrutiny since 2018 due to the FDA's investigation into potential links between grain-free diets (particularly those using peas, lentils, and potatoes as primary carbohydrate sources) and non-hereditary dilated cardiomyopathy (DCM). Unless your dog has a diagnosed grain allergy (which is rare — true grain allergies account for less than 1% of canine food allergies), grain-inclusive natural diets are generally considered safer based on current evidence.
How is a dog's digestive system different from a human's when processing natural foods?
Several key physiological differences affect how dogs and humans process the same natural ingredients: (1) Dogs have a shorter gastrointestinal transit time (12–30 hours vs. 24–72 hours in humans), meaning food passes through faster. (2) Dogs have a much more acidic stomach (pH 1–2 vs. pH 4–5 in humans), which allows them to handle higher bacterial loads in food. (3) Dogs lack salivary amylase — starch digestion begins in the small intestine, not the mouth. (4) Dogs have a relatively larger stomach capacity as a percentage of body weight, adapted for gorging behavior inherited from wild ancestors. (5) Dogs cannot synthesize vitamin D from sunlight and must obtain it entirely from dietary sources — making the vitamin D content of their natural food critical.
Sources consulted: Axelsson, E. et al. (2013). Nature, 495(7441); FDA Grain-Free Diet Investigation (2018–present); Merck Veterinary Manual — Digestive System in Dogs; FDA — Pet Food Labeling Guide; AVMA Position on Raw Pet Foods.
Priya Sutaria
All our authors care for dogs every day — read more of their work on the authors page.
