From the previous posts, we know that most of the words used to describe dog food have no value in describing what is appropriate for your dog.
Basic rules for buying dog food:
1. Larger named companies (Iams, Purina, Hills, Royal Canin, etc) usually have more stringent quality control. That is why recalls are made for these brands- they are routinely screening for problems with their food and alerting you before your dog becomes ill. Large companies also have expert nutritionists and food scientists who perform extensive research on food for your dog.
2. Be wary of food listing fresh fruits/vegetables or meats as their first few ingredients. This looks like a good thing but ingredients are listed in order of weight- fresh fruits/vegs and meats have a lot of water content. What these are adding to the nutritional content of the food may be very minimal and added only to increase our perception of a better food.
3. Grain free is not a good thing for the majority of dogs. Whole grains contain valuable nutrients including protein, vitamins, minerals, and fiber while keeping fat and calories lower than meat products. Allergies to grains are very uncommon in dogs. Substituting more expensive starches like potato or tapioca can give the food fewer nutrients, higher glycemic index (spikes in blood sugar) and less fiber than whole grains while costing you more.