Different dogs have different diets. Even dogs of the same size have different energy needs, and not all dogs need as much protein as others. Nonetheless, when looking at the best dog foods there are enough common denominators that it is possible to decide which dog foods do better than others. Healthy dog food is usually meat-based with few preservatives and plant material, and has some added ingredients in order to round out the diet of the dog. While this usually means vitamins and other oils, it can mean a variety of other ingredients may find themselves into dog food. It is thus just a matter of deciding which ingredients are more important for the dog.
First off, while dogs in general have problems digesting plant matter as their digestive tracts are simply not set up to deal with the cellulose of plant cells, this does not mean that dogs require a meat-based diet as much as other carnivores due to their long established relationship with humans. This means that a perfectly good dog food can contain a lot of plant material, such as soy and cornmeal, without really affecting the health of the dog. That is an important distinction between those looking for a good meal for their dogs and those looking for the best food for dogs.
That said, the top dog foods do have a lot of actual meat in them rather than plant materials. For dogs there is an almost visceral need to feed on actual protein, and the constant exercise some dogs get almost requires it. While some owners supplement the dog food with eggs and other raw meats, the best dog foods incorporate animal material from a wide variety of sources seeking the best possible dietary balance for the dog that will be eating it, while allowing for the difference between different breeds. The top dog food may be different for different dogs.
While a good dog food will meet the needs for any dog, it may not be best for all dogs. For dogs that lead active lives, such as work dogs and even some support animals, the best dog foods incorporate a wide variety of different strategies in order to make sure that they are the best dog foods. This means varying the amount of dairy products incorporated into them, as well as sources of roughage in order to make the food that much more healthy. Additionally, a number of oils and vitamins are added to the food in order to make healthy dog food even healthier.
The top dog foods are designed to make for some very healthy animals. As usual, for best results consult with a veterinarian before switching dog foods; because of the difference in dietary needs and other conditions, two dogs even of the same species and age may not do as well with the same food. Keep that in mind and the best dog foods will be possibly even better. Keep an eye on your dog in order to make sure that it is working out, and you may have found a new best dog food.