No, adding other ingredients to our diets is not necessary (except for our base mixes which require protein to be added). Our foods are formulated to meet the AAFCO Nutrient Profiles and can be fed alone. However, many of our customers love to mix up their companion’s meals with home-made extras. We encourage this because we think pet’s deserve variety in their diets just like we humans do. Our foods have balanced calcium: phosphorus ratios to allow you to add in extras in moderate amounts without throwing these important minerals outside their optimum ratios.