Why High Protein Foods are not necessarily good for your pet!
A common misconception among pet owners is the fact that pets require diets consisting almost purely of meat. This however is not true. The reason for this is probably that many pet food companies have used marketing tactics to make pet owners believe in high protein diets, but the truth is that high protein diets can actually be harmful for pets. According to new European legislation, pet food companies are no longer allowed to declare the meat percentage in their products, but only the percentage of protein that have animal origin. This can be a problem in some cases because the percentage of protein in a product does not state anything about neither the quality nor the source of protein, which is actually the most important thing to be aware of.
Proteins are the building blocks of the body and therefore essential for the daily function. However, when pets eat too much protein they cannot use it all at the same time. Excessive amounts of protein cannot be stored in the body for later use, and therefore the animal will have to excrete it through the urine via the kidneys. This means that if a pet is fed high protein diets for a long period there is a risk of overloading the kidneys and the development of kidney disease.
Concentration of essential amino acids and digestibility is what determines the quality of a protein. Proteins of good quality ensures the animal ideal proportions of essential amino acids, whereas the animal does not properly digest poor quality proteins. Good quality proteins are more bioavailable for pets, and can better be absorbed by the body, thus the quality of the protein should be more important than the actual amount. Another issue is that protein is a nutrient very high in calories, so when feeding high protein diets there is a greater risk of the animal becoming overweight. Finally, high protein diets also makes it difficult to maintain the right calcium-phosphorus ratio and this is especially a problem for puppies and kittens because it can lead to abnormal joint and bone development predisposing the animals for arthritis in the future.
The AAFCO (The Association of American Feed Control Officials) has established that canine pet foods containing good quality protein sources should contain at least 22 % for growth and 18 % for maintenance. For commercial cat foods AAFCO recommends a protein content of at least 30 % for kittens and 26 % for adult cats. These recommendations are daily allowances and should not be seen as minimum requirements or optimal intake levels. There is no scientific evidence that increasing the amount of protein is better as long as the daily requirements are met. On the contrary, there are several health issues to be aware of when choosing high protein diets for your pet. Thus, recommendations are that protein content in maintenance pet foods for adult animals do not exceed 30 % for dogs and 45 % for cats.
The reason that cats and dogs require protein is that they have a requirement for essential amino acids. Out of the 22 amino acids, 10 of them are essential to dogs and 11 for cats. Some of the more important ones are arginine, lysine, methionine tryptophan and taurine. Arginine and taurine are only present in animal proteins such as meat, which is why both dog and cat food should contain some degree of animal protein.
As a pet owner, one should also be aware that excess protein makes the food more expensive. Dogs and cats use some of the excess protein for energy. However, this is a much more expensive energy source than e.g. carbohydrates which is actually also a better source of energy for the dog and cat.
When all aspects are taken into account, there is no nutritional nor scientifically reasons supporting giving animals excessive amounts of dietary protein.