The trick is to provide the six basic nutrients in a balanced diet, factoring in the calories that will suffice for your dog's growth, activity, and restoration. In addition, your dog's daily diet must contain vitamin and mineral supplements in balanced concentrations. Too much of one mineral may interfere with absorption of another; too little of a mineral may interfere with vitamin use or other mineral use.
If you plan to feed your pet fresh food, you want to make sure that you provide him with all the nutritional building blocks he needs to maintain a healthy body. Animal protein should be combined with vegetables, pasta, rice, cereals and other foods to provide all the protein, carbohydrates, fats, vitamins and minerals needed.
If you still opt for the convenience of commercial foods, it is wise to become versed in the art of decoding dog food ingredient labels so that you can be assured that the nutritional value matches (or, ideally, surpasses) the marketing technique employed.
The dog food manufacturers spend a great deal of time, energy and advertising revenue to persuade us that their products are natural and nutritionally complete. That would indicate,
1) That is what consumers would like the product to be, and
2) That is what the product should be.
Doesn't it make sense, then, that you select food for your dog that you know to be healthful and nutritionally sound? If you're still buying commercial dog food, you aren't feeding your dog what it needs and deserves.