Protein is essential to a dog's diet. It is necessary for its growth and development and more importantly, in its structural makeup and immune system. As dogs are generally energetic and athletic, they burn calories gained from protein and convert these enzymes into fat. The building blocks that make up proteins, amino acids, are either consumed or synthesized. A deficiency in these amino acids may cause severe health side effects. Levels of protein vary; however, protein itself is vital to a dog’s bodily function as it maintains the structure of skin and ligaments, needed for the production of new tissues, maintains metabolic processes and is a necessary nutrient for the repair of tissues. Low protein dog food may be necessary in a dog’s diet if it is suffering from urinary tract infection, urinary stones, early kidney disease or chronic renal failure.

In a dog's diet, a higher percentage or consumption of protein does not mean it is better than other brands of food. If the food comes from a good source (real chicken or real lamb meat), then the protein is beneficial to the dog's diet. It is pivotal to evaluate the source of the protein in dog food and not just the amount when comparing and contrasting pet foods. Optimal protein levels for different life stages and activity levels vary greatly for dogs. Senior dogs, due to weaker kidneys, generally require less protein than active adults. However, the newest research shows it is not the proteins that cause damage to kidneys in dogs as much as it is the phosphorus contained in the protein.

Low protein dog food contains a variety of different levels of amino acids and each protein has a varying ability to break down into amino acids. Egg, for example, contains high protein followed by fish and milk and beef. For a puppy, 28% of dietary intake should be protein while for an adult dog, 18%. The ideal diet for a dog with kidney or urinary health-related problems is one of high quality, low level protein. A diet which is high in complex carbohydrates containing ingredients such as whole grains, fruits, and low purine vegetables may help rid the body of extra uric acid. A diet with low protein, coupled with low fat, phosphorus, salt and purines are able to assist the body in metabolising the uric acid in the body.

While high protein intake is not much harm as it is converted to calories or into fat, a dog with a kidney problem may suffer from high protein diets. Low protein diets are usually low in nitrogen. These proteins are more digestible and therefore produce less nitrogen by products. Dogs with weak or damaged kidneys may not be able to handle diets with normal protein content and thus low protein dog food allows the body to handle excess protein and nitrogen more efficiently. In dogs with poor or damaged kidneys, a low protein diet can prevent the nitrogen content being too high in the bloodstream which may cause harm to other body tissues. Unless your dog has a kidney problem, adjusting the protein intake is not necessary. It is important to note that feeding a normal dog a low-protein diet is not ideal either.

High protein dog diets have been linked to aggressive behaviour. Lower protein dog food tends to offer better nutrition, palatability and digestibility. A healthy nutrition can also mean less medical bills. Ensuring your dog's diet is optimal will result in the difference you see in your dog's healthy skin, coat and energy level.