Good nutrition and a balanced diet are essential elements for good health in a dog. Your dog needs plenty of fresh water and should be fed good quality food in amounts just right to meet his energy requirements. Inadequate or excess intake of nutrients can be equally harmful.
Most dry dog foods are soybean, corn or rice based. Some of the better brands have meat or fish meal as the first listed ingredient. Although higher priced, they are worth looking into. Dogs eat less of the higher quality products, thus reducing the cost. Dry dog foods also have greater "caloric density" which means simply, there is less water in a cup of food as compared to a canned food diet. This is not a big issue for our smaller canine friends, but large dogs may have difficulty eating enough volume of canned food to fulfill their caloric needs (because they also get a lot of water in that food). Overall, the choice of "dry" vs. "canned" vs. "semi-moist" is an individual one, but larger dogs (such as those greater than 30 pounds) should be fed a dry or semi-moist food in most circumstances
Proteins, fats and carbohydrates are necessary for energy. Dietary requirements for dogs can vary according to activity and stress levels and medical history. Dogs expend energy in many different ways. For example, outdoor dogs are likely to experience increased levels of exercise and thus require a higher percentage of protein and fat for energy production than a dog who stays indoors most of the time. Dogs in various life stages [including puppy ("growth"), adult and senior ("geriatric")] require different amounts of nutrients. Special situations such as pregnancy and nursing puppies can dramatically affect nutritional needs. Working dogs need more calories, while the "couch potato" needs less (just like us!).
The Association of American Feed Control Officials (AAFCO) is an organization that publishes regulations for nutritional adequacy of "complete and balanced" dog and cat foods. Your pet's food should conform to minimal AAFCO standards. Diets that fulfill the AAFCO regulations will state on the label: "formulated to meet the AAFCO Dog Food Nutrient Profile for…(a given life stage).
Consider Your Dog's Age
Consider Your Dog's Body Weight
Always consult your veterinarian first regarding any specific foods or dietary adjustments required for a dog with heart, kidney, intestinal or liver disease, or for a dog with cancer. Special dietary measures may also be important for dogs with allergies, certain metabolic diseases, or other medical conditions.
There are a number of prominent manufacturers of high quality dog foods, including Iams (Eukanuba), Hill's (Science Diets), Nature's Recipe products, Nutra Max, Purina and Waltham, among others. Follow the label recommendations, but use your own judgment in determining how much to feed.