Ratios for ingredients in dog food vary among manufacturers, as well as for a dog's age, breed and activity level. The Association for American Feed Control Officials (AAFCO) is an association of local, state and federal agencies that suggests the amount of each nutrient by percentages, not ratios. Commercial pet food that is nutritionally complete or balanced will include AAFCO's statement that guarantees the pet food meets nutrient requirements.
Protein is comprised of 23 amino acids—dogs manufacture 13 of the 23. The other 10 amino acids must come from meat products and plant sources. However, animal proteins have a higher biological value than vegetable proteins. The AAFCO approves food that has a minimum of 22 percent protein for growth and reproduction stages and a minimum of 18 percent for adult dogs. Working dogs need more than 30 percent protein, according to the Journal for Nutrition. Therefore, an adult dog food has an approximate ratio of 5:1 of other ingredients to protein.
Fat supplies energy, helps transport fat-soluble vitamins and maintains a healthy skin and coat. However, too much fat in a dog's diet can lead to weight gain and obesity. Fortunately, a dog's muscles are more adapted to using fat than a human's, so working dogs and exercising dogs are able to handle 50 percent or more fat in their diet. The AAFCO recommends 8 percent fat for growth and reproduction stages and 5 percent for adult dogs. Therefore an adult dog food has an approximate ratio of 20:1 of other ingredients to fat.
Carbohydrates are a direct source of energy. These stop protein from converting to glucose: without carbohydrates, the protein your dog consumes would not be available for tissue building and maintenance. Primarily found in grains and vegetables, carbohydrates are sugars, starches and fiber. Not only do they provide energy, but the fiber helps in digestion. The AAFCO has no recommendations for the proper ratio of carbohydrates in your dog's food.
Minerals and Vitamins
Minerals are needed for structural building and chemical reactions. Calcium and phosphorous are two minerals that need to be consumed in proper ratios for good health. Calcium for growth and reproduction should be 1 percent of the diet, and for most adult dogs it should be 0.6 percent. It should not exceed 2.5 percent. Phosphorous for growth and reproduction should be 0.8 percent and for most adult dogs 0.5 percent. It should not exceed 1.6 percent. Complete and balanced dog food has the correct ratios of vitamins. No additional vitamins are needed for your dog.