Dogs need a diet built on animal protein and fat, with smaller amounts of carbohydrates, plus essential vitamins and minerals. When given free choice, dogs naturally gravitate toward meals where about 30% to 44% of calories come from protein and 50% to 63% from fat, with very little from carbohydrates. That natural preference is a useful starting point, but what your dog actually needs depends on age, size, and activity level.
Protein, Fat, and Carbohydrates
Protein is the foundation of a dog’s diet. Dogs require 10 essential amino acids they cannot make on their own, including lysine, tryptophan, and arginine, all of which come from protein-rich foods like meat, fish, and eggs. Industry feeding guidelines recommend commercial dog foods contain at least 18% protein on a dry matter basis for adult dogs, and at least 22.5% for puppies. More active dogs and working breeds generally benefit from higher protein levels within that range.
Fat provides the most concentrated source of energy and helps dogs absorb certain vitamins. It also supports skin and coat health. There is, however, an upper limit: the National Research Council sets a safe ceiling at about 33% fat on a dry matter basis, because very high-fat diets raise the risk of pancreatitis, a painful and potentially dangerous inflammation of the pancreas.
Carbohydrates are not strictly essential for dogs, and in feeding studies dogs consistently choose low-carbohydrate options when given a choice. Still, whole grains, vegetables, and other carbohydrate sources provide fiber, vitamins, and a practical energy source. Most commercial dog foods include moderate carbohydrates, and healthy dogs digest them without trouble.
How Much to Feed
Veterinarians estimate daily calorie needs using a formula based on body weight in kilograms. You take your dog’s weight in kilograms, raise it to the power of 0.75, then multiply by 70. That gives a resting energy requirement. For a typical neutered adult dog, you then multiply that number by about 1.4 to get their daily maintenance calories. A 10-pound (4.5 kg) neutered dog, for example, needs roughly 302 calories per day.
Intact dogs, highly active dogs, and dogs in cold environments need more. Overweight or sedentary dogs need less. The calorie count on your dog’s food label, combined with this kind of calculation, gives you a much more accurate portion size than the broad ranges printed on most bags. If your dog is gaining or losing weight unexpectedly, adjusting portion size by 10% to 15% and reassessing after two weeks is a reasonable approach.
What Puppies Need Differently
Puppies are growing fast, and their food has to keep pace. Puppy formulas contain more protein (at least 22.5% versus 18% for adults), more fat (at least 8.5% versus 5.5%), and significantly more calcium (1.2% versus 0.5%) to support developing bones and teeth. They’re also more calorie-dense overall.
This matters in both directions. Feeding adult food to a puppy can leave them short on critical nutrients during a window when deficiencies cause lasting harm. Feeding puppy food to an adult dog, on the other hand, delivers excess calories and calcium that can contribute to weight gain and, in large breeds especially, skeletal problems. Large-breed puppies have their own considerations: calcium maximums are capped at 1.8% for puppies that will exceed 70 pounds as adults, because too much calcium during rapid growth can cause joint and bone disorders.
Fruits and Vegetables Worth Adding
Plenty of whole foods make safe, nutritious treats or meal additions for dogs. Blueberries are packed with antioxidants that support immune function. Carrots provide fiber, beta-carotene, and vitamin A, and most dogs enjoy the crunch. Apples (with seeds removed) offer vitamins A and C plus fiber. Pumpkin is high in fiber and widely recommended by veterinarians as a digestive supplement, particularly for dogs with loose stools or mild constipation.
Sweet potatoes are rich in vitamins, minerals, calcium, and fiber. Watermelon (seedless, without rind) provides vitamins A, B-6, C, and potassium, and works well as a hydrating summer treat. Spinach is one of the most nutrient-dense vegetables you can share, with high levels of iron, beta-carotene, and calcium. Cucumbers, peeled to avoid the waxy skin, offer vitamin C with very few calories. Zucchini rounds out the list with a mild flavor and a good mix of vitamins and fiber.
These should be treats or supplements, not the bulk of the diet. A good rule of thumb is keeping treats and extras to 10% or less of total daily calories.
Foods That Are Dangerous for Dogs
Several common human foods are genuinely toxic to dogs, not just unhealthy but capable of causing organ damage or death.
- Chocolate and coffee contain compounds called theobromine and caffeine that dogs metabolize much more slowly than humans. Dark chocolate and baking chocolate are the most dangerous. Even small amounts can cause vomiting, rapid heart rate, and seizures.
- Grapes and raisins can trigger sudden kidney failure in some dogs. The exact toxic compound has never been identified, and there’s no way to predict which dogs are susceptible, so all dogs should avoid them entirely.
- Onions, garlic, leeks, and shallots contain sulfur compounds that damage red blood cells, leading to anemia. Garlic also contains agents that drop blood pressure. Cooked, raw, or powdered forms are all harmful.
- Xylitol, an artificial sweetener found in sugar-free gum, candy, peanut butter, and baked goods, causes a rapid, dangerous drop in blood sugar and can lead to liver failure.
- Macadamia nuts affect the muscles, digestive system, and nervous system through an unknown mechanism. Symptoms include weakness, vomiting, tremors, and fever.
- Avocado contains persin, a compound found in the fruit, pit, and leaves that can cause vomiting and diarrhea.
- Alcohol is far more toxic to dogs than to humans relative to body size. Even small amounts of beer, wine, or liquor can be dangerous, and the hops in beer are independently toxic, potentially causing seizures, elevated temperature, and death.
The Grain-Free Diet Question
Starting in 2018, the FDA began investigating reports of dilated cardiomyopathy (a serious heart condition) in dogs eating grain-free diets. The pattern was striking enough to draw national attention. Most of the diets linked to these cases contained high amounts of legume ingredients like peas and lentils, which are commonly used as grain substitutes. Notably, both grain-free and some grain-containing formulas with high legume content were associated with reports.
As of the FDA’s most recent updates, the agency still does not know the specific connection between these diets and heart disease. Reports have declined since the 2018 to 2020 peak, but the investigation remains open. The FDA has not pulled any products from the market, stating there is no definitive evidence the diets are inherently unsafe. However, they continue to explore how these diets may interact with genetics and other factors.
If your dog is currently eating a grain-free diet and doing well, there’s no need to panic. But if the diet relies heavily on peas, lentils, or other pulses as primary ingredients, it’s worth discussing alternatives with your vet, particularly for breeds already predisposed to heart conditions.
Water Needs
A healthy dog should drink roughly one ounce of water per pound of body weight each day. A 30-pound dog, for instance, needs at least 30 ounces, or just under four cups. Dogs eating dry kibble typically drink more than those on wet or raw diets, since canned food can be 70% to 80% water by weight. Hot weather, exercise, nursing, and illness all increase water needs. If your dog suddenly starts drinking significantly more or less than usual, that shift itself can be an early sign of conditions like kidney disease or diabetes.
Choosing a Commercial Dog Food
The simplest way to ensure your dog gets complete nutrition is to look for foods labeled “complete and balanced” that meet AAFCO nutrient profiles. This label means the food has been formulated to meet minimum (and in some cases maximum) levels for over 30 essential nutrients, including vitamins A, D, and E, B vitamins, and minerals like calcium, phosphorus, zinc, and selenium. It also means the food is designated for a specific life stage: growth, adult maintenance, or all life stages.
Beyond that label, the ingredient list tells you what the food is actually made of. Named animal proteins (chicken, beef, salmon) listed in the first few ingredients are generally preferable to vague terms like “meat meal” or “animal by-products.” The best foods use recognizable whole-food ingredients and avoid long lists of artificial colors, flavors, or preservatives. Price doesn’t always correlate with quality, but extremely cheap foods often rely on fillers and lower-quality protein sources that dogs digest less efficiently, meaning more waste and less nutrition per cup.