Here is a great article on everything you wanted to know about protein, and probably some things you didn't. :wink: I tend to stay somewhere between 21%-28% protein.
Protein Requirements for Good Nutrition
Veterinary & Aquatic Services Department, Drs. Foster & Smith, Inc.
Proteins are the building blocks in animal nutrition. They are one of the most important nutrients in the diet and are currently one of the most widely debated. For around twenty thousand years as dogs, and for several million years before that as wolves, the only problem canines had with protein was getting enough of it. Dogs ate a primarily meat diet and with that consumed a high percentage of their diet as protein. With their meat diet they also got a fair portion of fat and a little fiber and carbohydrate thrown in, but primarily they ate meat. Cats were pretty much the same only they were even stricter carnivores and did not eat any carbohydrates.
The discussion about protein started around World War II when commercial dog foods became more available and they began to replace the traditional meat and meat by-product diet. At first, the cheaper forms of leftover meat were put into the food with little regard for flavor or fashion. But with the interest in health as related to diet, a whole new generation of dog foods have entered the market. These quality foods challenge the earlier foods by promoting a product that is better than ever for our pets. At the center of debate for the newer products is protein, its source, digestibility, and quantity. Hopefully this article will answer some of the questions concerning protein in your pet