There is no single best dog food; the best dog food for your dog depends on many factors. If your dog is an adult and healthy, then any commercially prepared dog food formulated for adult dogs should be appropriate for his needs. However, if your dog is a puppy, elderly or suffering from a systemic medical condition such as liver disease, then he may have specialized dietary needs.
Knowing What Your Dog Needs
Puppies and elderly dogs have different dietary needs than healthy, adult dogs. Also, pregnant and lactating dogs' dietary needs are different; pregnant and lactating dogs will need to eat a diet of puppy food, and will need to eat much more than normal.
If your dog is a puppy younger than one year of age, make sure you feed him a food specially formulated for puppies. Puppies have increased nutritional needs, because they are growing very quickly. Puppies need a lot of protein to support muscle growth; extra calcium supports bone development; fatty acids and other nutrients support brain and organ development. For these reasons, a food intended for adult dogs may not provide your puppy with the nutrition he needs.
By the same token, once your dog reaches his geriatric years, around ten years of age and older, switch him to a food specially formulated for older dogs. Older dogs experience a decrease in metabolic rate due to a decline in overall functioning; a food formula for senior animals takes this into account, providing fewer calories so your elderly dog doesn't get fat. A food formulated for senior dogs, however, will have slightly more protein than a food intended for younger adult dogs, and they may also contain slightly more vitamins and minerals to prevent your senior dog from developing one of the many illnesses that can accompany old age.
Feeding Your Healthy Adult Dog
The best dog food for a healthy adult dog is dry dog food. Prepared dry food contains all the nutrients that your dog needs. Dry kibble helps keep your dog's teeth clean, whereas wet dog food can lead to increased tooth decay.
A good rule of thumb when selecting dog food for a dog of any age is neither to go too cheap nor too expensive. Choose a brand in the middle price range; it will be of somewhat higher quality than the cheapest brands, while it may be of equal quality to the most expensive brands. Consider feeding an all-natural dog food; while these may seem more expensive, you'll find yourself feeding less because these foods contain more protein and less filler.
Dogs With Special Dietary Needs
If your dog suffers from a systemic illness such as liver or kidney disease, he'll need a special diet to help control his condition. Your vet will no doubt recommend a prescription food to help control your dog's liver, kidney or other systemic illness. Additional supplements may be of great benefit if your dog suffers from kidney, liver or other systemic illness.