Optimum nutrition demands that protein, fat, carbohydrate and micronutrients such as minerals, vitamins, and enzymes are in balance with each other. An imbalance of calcium and phosphorus in a dog's diet would lead to health disasters. Meat is high in phosphorus but low in calcium so too much meat is also not good for dogs over long periods of time.
Therefore while buying a "Complete & Balanced Dog Food" need to look for Protein content, Fat content, Preservatives via Vitamin E and/or C and Omega Fatty Acid. But keep in mind that supplementation can be harmful, especially calcium supplementation to a pregnant bitch.