Advocates of raw food diets often implicate the grains and “fillers” in processed, commercial foods as being bad nutrition for pets. A “filler” is a food ingredient with little or no nutritional value. This certainly doesn’t apply to corn or other grains. Corn, oats, rice, barley, wheat, and other grains contain protein, vitamins, and minerals. Corn provides a lot of needed amino acids and is a highly digestible carbohydrate the body uses for energy. While cats require a meat-based diet, there is nothing inherently wrong with feeding food that contains some grains. Pets with allergies MIGHT have a sensitivity to wheat or corn, but it could also be to chicken, lamb, seafood, or beef. Talk to your veterinarian about trying a “novel protein” diet and see if that helps before trying a raw food diet.
Many people are trying a gluten-free diet, but celiac disease is very rare in dogs and has been reported primarily in Irish Setters. Pets (and people) with celiac disease react to the proteins (gluten) in wheat, rye, and barley. The protein in corn gluten does NOT cause GI problems, even in individuals with celiac disease. If your pet is doing just fine (ie. no vomiting, normal stool, nice coat) on the food you are currently feeding, there is no need to switch to one without corn or grains.
Remember, your veterinarian is your BEST source of nutritional advice, not the sales clerk at a pet store. What works for one pet may not be optimal for your pet, so sometimes trying different foods is necessary.