The health issue in which a dog's diet would change is any kind of renal problem like renal failure. Some other issues like gastrointestinal diseases would also require you to moderately regulate the protein intake for better digestion. If you give your dog a good quality protein-based diet over the years, and you stick to the right kind of protein, it is less likely for your dog to develop a kidney problem. The decisions of protein content in your pet's food must be taken early on. This affects their long term well being. If we are careful from the beginning, we can help prevent many health issues.