Dog Nutrition
Frequently Asked Questions
Scientific answers based on AAFCO 2023, WSAVA 2022 and NRC 2006 standards, prepared by Doç. Dr. Mehmet ÇOLAK
For adult dogs, 2 meals a day (morning and evening) is the standard approach. Puppies up to 6 months of age usually need 3-4 meals daily. Large-breed puppies are generally better managed with 3 meals, because one large meal may increase the risk of gastric dilation-volvulus (GDV). Senior dogs and dogs with digestive sensitivity may also do better with 2-3 smaller meals. Free feeding (keeping the bowl full at all times) strongly increases the risk of obesity.
Yes. There are meaningful nutritional differences. Large-breed formulas usually have a lower calorie density to reduce obesity risk, a more controlled calcium-phosphorus balance that is critical for skeletal development, and often include ingredients such as glucosamine and chondroitin. In large-breed puppies, calcium should ideally remain between 1.2-1.8% on a dry matter basis. Excess calcium can contribute to developmental orthopedic problems. The NRC 2006 recommendations clearly support breed-size-specific growth nutrition in large puppies.
This remains controversial and requires caution. Advocates of BARF (Biologically Appropriate Raw Food) emphasize its natural basis. However, the AVMA, WSAVA, and AAFCO have all issued warnings about raw feeding. The main risks are Salmonella, E. coli, Listeria, and Toxoplasma exposure for both the dog and the owner, as well as a high risk of nutrient imbalance. More than 60% of homemade raw diets have been shown to be incomplete or imbalanced (WSAVA 2022). If a raw diet is used, it should be formulated and supervised by a veterinary nutrition professional.
Grain-free food is not automatically superior. In 2018-2019, the FDA investigated a possible link between grain-free diets, especially those high in peas and lentils, and dilated cardiomyopathy (DCM) in dogs. The concern does not appear to be grain itself, but rather the heavy reliance on legumes in some formulations. True grain allergy is uncommon in dogs, affecting roughly 1-2%. If there is no well-founded suspicion of a grain allergy, a balanced grain-inclusive diet can be a very good choice. If grain-free food is selected, it is safer to avoid formulas with excessive legume content.
Foods that should never be given include chocolate (theobromine toxicity affecting the heart and nervous system), grapes and raisins (associated with kidney failure), onion, garlic, and leeks (thiosulfate-related hemolytic anemia), xylitol (severe hypoglycemia and liver failure), avocado (persin-related toxicity), raw bread dough and alcohol, and macadamia nuts. If poisoning is suspected, urgent veterinary advice is required.
Under AAFCO rules, ingredients are listed in descending order by weight. That means the first 3 ingredients make up a substantial part of the formula. Ideally, the first ingredient should be a clearly identified animal protein source such as chicken, salmon, or lamb, rather than vague wording like 'meat' or 'poultry'. One important detail: 'fresh chicken' contains water, so its contribution falls after processing, whereas 'chicken meal' is a more concentrated protein source. VetKriter's VetScore system evaluates this ingredient hierarchy objectively.
This depends on breed size. Small breeds (< 10 kg): 9-12 months. Medium breeds (10-25 kg): about 12 months. Large breeds (25-45 kg): 12-18 months. Giant breeds (> 45 kg): 18-24 months. Staying on puppy food too long can promote obesity. The transition should be done gradually over 7-14 days: 25% new food at first, then 50%, then 75%, before a full switch.
Dogs are generally considered senior from 8-9 years in small breeds and 6-7 years in large breeds. Senior diets are usually lower in calories because metabolism slows with age, but they should still provide high-quality protein to preserve lean muscle mass. In many senior dogs, protein restriction is not recommended unless there is a specific medical reason. Omega-3 fatty acids support joint and cognitive health, and lower sodium may be helpful in dogs with heart disease. If kidney disease is present, phosphorus restriction may be needed under veterinary guidance.
According to AAFCO 2023, the minimum crude protein level for adult dogs is 18% on a dry matter basis, while puppies require at least 22%. These are minimums rather than ideal targets. For active or working dogs, protein levels around 25-30% are often more appropriate. Protein source also matters: animal proteins such as chicken, turkey, beef, and fish generally offer better bioavailability than plant proteins. Amino acid balance is important as well, especially lysine, methionine, and cysteine.
AAFCO 2023 recommends a minimum crude fat level of 5.5% on a dry matter basis for adult dogs, and at least 8.5% for puppies. Fat is an important concentrated energy source and is needed for the absorption of fat-soluble vitamins A, D, E, and K. Linoleic acid (omega-6) is an essential fatty acid for dogs. Omega-3 fatty acids such as EPA and DHA are important for brain, eye, skin, and joint health. In highly active dogs, fat levels may reasonably increase to 15-20%.
AAFCO does not define a minimum carbohydrate requirement for dogs because dogs can generate glucose through gluconeogenesis. In commercial dry foods, carbohydrate content is commonly in the 30-60% range. Excessively high carbohydrate levels may contribute to obesity and can complicate diabetes management in predisposed dogs. On the other hand, carbohydrates can be a useful energy source for active dogs. Carbohydrate is usually not listed directly on the label and is estimated by difference: 100 - (protein% + fat% + moisture% + ash% + fiber%) = carbohydrate%.
No. 'By-product' does not automatically mean poor quality. Under the AAFCO definition, by-products may include organs such as liver, kidneys, heart, and lungs. These tissues can actually provide highly bioavailable protein, vitamin B12, and iron. A clearly named ingredient such as 'chicken by-product meal' is much more acceptable than a vague label such as 'meat by-product'. VetKriter's VetScore evaluates this kind of ingredient quality objectively rather than by marketing terms alone.
A sudden diet change can cause digestive upset, including diarrhea, vomiting, and reduced appetite. A standard transition plan over 7-10 days works well for most dogs: days 1-2 use 75% old food and 25% new food, days 3-4 use 50/50, days 5-6 use 25% old and 75% new, and then switch fully. In dogs with particularly sensitive digestion, the transition may need to be stretched to 2-3 weeks. If gastrointestinal signs continue during the change, veterinary advice is needed.
Obesity affects approximately 25-40% of dogs. On the body condition score (BCS) scale, scores of 6-9/9 indicate excess body condition. Management: calculate the daily calorie requirement based on ideal body weight, choose a higher-protein and lower-fat diet, control portions carefully, and increase daily exercise. A practical weight-loss target is 1-2% body weight per week. Weight loss that is too rapid can increase lean muscle loss. A structured plan under veterinary supervision gives the best results.
Foods that must be avoided include: chocolate and cocoa because of theobromine toxicity, grapes and raisins because of kidney injury risk, onions, garlic, and leeks because they can cause hemolytic anemia, xylitol because it can cause severe hypoglycemia and liver failure, avocado because of persin toxicity, macadamia nuts because of neurologic signs, alcohol because of central nervous system depression, raw bread dough because of alcohol production, and caffeine because it can trigger tachycardia and seizures. Any suspected ingestion requires immediate veterinary advice.
The intestinal microbiome plays an important role in canine health. Prebiotics such as FOS, MOS, and inulin act as nutrients for beneficial intestinal bacteria and help regulate gut function. Probiotics such as Enterococcus faecium or Lactobacillus acidophilus may help support immune balance and reduce the risk of diarrhea in some dogs. Probiotic supplementation is often considered after antibiotic use or during stressful periods. It is important to use strains that are appropriate for dogs and supported by product quality data.
The omega-6 to omega-3 ratio matters because it influences the body's inflammatory balance. High omega-6 intake may promote a more pro-inflammatory state, whereas omega-3 fatty acids such as EPA and DHA have anti-inflammatory effects. A practical target range is often 5:1 to 10:1 (omega-6:omega-3). Dogs can convert some ALA into EPA and DHA, but this conversion is limited, so direct marine sources such as fish oil are usually more effective. Omega-3 support may be beneficial for skin, joints, and brain function.
These terms are not legally precise quality guarantees. In particular, 'holistic' is not a regulated nutritional standard under AAFCO and is mainly used as a marketing term. More reliable quality indicators include an AAFCO 'complete and balanced' statement, a transparent ingredient list, a clearly identified animal protein near the top of the list, manufacturer transparency, and evidence from feeding trials. VetKriter's VetScore evaluates these more meaningful factors.
It is often recommended. After neutering, metabolic rate may decrease by 15-25%, which increases the risk of weight gain. Diets marketed for neutered dogs usually have a lower calorie density and a higher-protein, lower-fat profile. If a regular diet is still being used after neutering, the portion often needs to be reduced by 20-25%. Weight monitoring is especially important during the first 6 months after surgery, and body condition score should be checked regularly.
Homemade dog food can be healthy if it is properly formulated, but doing that well is difficult. Studies have shown that about 95% of homemade recipes contain at least one important nutrient deficiency. Commonly deficient nutrients include calcium, vitamin D, iodine, zinc, copper, and omega-3 fatty acids. If a homemade diet is used, it should ideally be designed with a veterinary nutrition specialist and monitored over time. Feeding meat alone is absolutely not nutritionally adequate.
Glucosamine and chondroitin are structural components of cartilage. Potential benefits: supporting joint cartilage, helping reduce clinical signs of osteoarthritis, supporting management of hip dysplasia in large-breed dogs, and improving comfort and mobility in older dogs. Evidence for their effectiveness is mixed, with some studies showing benefit and others showing limited effect. They are commonly included in foods or supplements for large-breed puppies and senior dogs.
L-carnitine is an amino-acid-derived compound that helps transport fatty acids into mitochondria. Potential benefits: supporting fat metabolism and weight management in overweight dogs, helping preserve lean muscle mass, and supporting heart muscle function. It is sometimes used in the nutritional management of dilated cardiomyopathy (DCM). Dogs can synthesize L-carnitine, but in some large breeds or in certain disease states, that synthesis may not be fully adequate. Supplementation can be useful in selected obese, cardiac, or large-breed dogs.
Calcium and phosphorus are essential for skeletal health. The ideal calcium-to-phosphorus ratio is generally between 1:1 and 2:1. In large-breed puppies, calcium intake is especially important; on a dry matter basis, calcium should generally stay around 1.2-1.8% because excessive calcium can contribute to developmental skeletal disease. Feeding meat alone disrupts this balance because meat is high in phosphorus and relatively low in calcium. AAFCO 2023 minimums for adult dogs are 0.5% calcium and 0.4% phosphorus on a dry matter basis.
Canine diabetes is typically insulin-dependent, more similar to type 1 diabetes. The diabetic diet approach usually includes higher fiber to reduce glucose fluctuations, carbohydrates with a lower to moderate glycemic effect, strict meal timing synchronized with insulin injections, and a consistent daily calorie intake. If the dog is overweight, controlled weight loss is also important. Feeding plans and insulin management should always be supervised by a veterinarian, with regular glucose monitoring.
Chronic kidney disease (CKD) is common in older dogs. Nutritional goals: phosphorus restriction is the single most important dietary measure for slowing progression. Protein restriction is debated in IRIS stages 1-2, but moderate restriction is generally recommended in stages 3-4. Higher moisture intake is helpful, so wet food is often preferred. Sodium restriction may be needed if hypertension is present, and omega-3 fatty acids such as EPA and DHA may help reduce renal inflammation. Prescription renal diets are designed to balance these needs.
Dogs can produce only limited amounts of vitamin D from sunlight, so dietary intake is still necessary. AAFCO 2023 lists a minimum of 500 IU/kg on a dry matter basis. Animal-derived ingredients such as fish liver oil and egg yolk are good vitamin D sources. Deficiency can contribute to skeletal disease, poor immunity, and muscle weakness, while excessive vitamin D can cause hypercalcemia and kidney injury. A properly balanced commercial diet should provide vitamin D in a safe and adequate range.
Zinc is an essential mineral for dogs. Signs of deficiency: skin lesions, especially zinc-responsive dermatosis in predisposed breeds such as Siberian Huskies and Alaskan Malamutes, hair loss or poor coat quality, growth delay, reduced immunity, and poor appetite. Diets high in phytates may reduce zinc absorption. AAFCO 2023 lists a minimum of 80 mg/kg on a dry matter basis. Zinc supplementation should be used with veterinary guidance, because excess zinc can also be harmful.
A 'complete and balanced' statement means the food is intended to meet all nutritional requirements on its own. Under AAFCO standards, this can be supported in two ways: 1) formulation method, where the nutrient profile is shown to meet published targets; or 2) feeding trial method, where the food has been tested in live animals, which is generally considered more robust. If a label says the food is only complementary, it is not nutritionally sufficient as the sole diet.
Additives often viewed less favorably include: synthetic antioxidants such as BHA (E320) and BHT (E321), and ethoxyquin, which has historically been used to preserve fats such as fish oil. Artificial colors such as Red 40 or Yellow 5/6 may increase the risk of unnecessary exposure without nutritional benefit and can be problematic in sensitive animals. Propylene glycol is not a routine concern in most dog foods but high exposure is not desirable. Preferred alternatives are natural preservatives such as tocopherols (vitamin E), ascorbic acid (vitamin C), and rosemary extract.
Food allergy affects roughly 1-2% of dogs. Typical signs: chronic itching, especially affecting the ears, paws, and groin; recurrent ear infections; gastrointestinal signs such as chronic diarrhea or vomiting; and skin redness or lesions. Diagnosis: the gold standard is an 8-12 week elimination diet using either a novel protein with a novel carbohydrate or a hydrolyzed protein diet. Blood tests are not considered reliable for diagnosis. Common dietary triggers include beef, dairy, chicken, and wheat.
Yes, the starch source can matter. Rice is usually highly digestible and is often well tolerated. Potato is gluten-free and has a moderate glycemic effect, but very high use has drawn attention in DCM-related investigations. Corn is also highly digestible and can be a useful energy source with a relatively low allergenic potential in most dogs. Wheat contains gluten and may be less suitable for some sensitive dogs. Peas and lentils have been discussed in the FDA's DCM investigation when present in very high amounts. The key issue is balance and formulation quality rather than a single ingredient alone.
Unlike cats, dogs can synthesize taurine from methionine and cysteine, so taurine is not always strictly essential. However, synthesis may become inadequate in some situations, including low-protein diets, some grain-free or legume-heavy formulas, and in certain large breeds. During the FDA's 2018-2019 DCM investigation, taurine deficiency was proposed as one possible mechanism in some diet-associated cases. Taurine content therefore becomes particularly relevant in large breeds and breeds considered at higher risk for dilated cardiomyopathy.
Dogs can convert beta-carotene to vitamin A, but this conversion is not highly efficient. For that reason, direct animal-based vitamin A sources such as liver or fish oil are often nutritionally valuable. AAFCO 2023 sets a minimum of 5000 IU/kg on a dry matter basis. Vitamin A deficiency can contribute to night blindness, skin problems, reproductive issues, and impaired immunity. Excessive intake, however, can lead to hypervitaminosis A with skeletal and liver damage. A balanced commercial diet is designed to stay within the appropriate range.
Working dogs such as herding dogs, sporting dogs, and search-and-rescue dogs have very high energy demands. Nutritional principles: a higher fat content, often around 20-30%, because fat is the most efficient fuel for endurance work; higher protein, often around 28-35%, for muscle maintenance and repair; and moderate carbohydrates to support shorter bursts of intense activity. Feeding is usually best done 2-3 hours before work, with protein intake soon after exercise. Adequate hydration is essential, and during prolonged heavy work, electrolyte support may also be helpful.
Vitamin E (tocopherol) is a strong antioxidant and also serves as an important nutrient. Benefits: it protects cell membranes from oxidative damage, supports immune function, helps maintain skin and coat quality, and helps protect omega-3 fatty acids from oxidation. AAFCO 2023 sets a minimum of 50 IU/kg on a dry matter basis. Foods with higher fat content usually need more vitamin E for proper oxidative stability. Natural tocopherols are generally preferred over synthetic antioxidant systems when formulation quality is otherwise adequate.
Iodine is required for the production of thyroid hormones (T3 and T4). Signs of deficiency: hypothyroid-like changes such as weight gain, lethargy, hair loss, and cold intolerance; goiter; poor growth in puppies; and reproductive problems. Iodine deficiency is seen more often in poorly balanced homemade diets. AAFCO 2023 gives a minimum of 1.0 mg/kg on a dry matter basis. Balanced commercial foods are formulated to meet this need, and it is important to remember that excess iodine can also contribute to thyroid dysfunction.
All answers on this page are prepared based on AAFCO 2023, WSAVA 2022 and NRC 2006 standards and current scientific literature.
About Us