According to Merriam-Webster dictionary, “nutrition is the act or process of nourishing or being nourished; specifically the sum of the processes by which an animal or plant takes in and utilizes food substances.” The key word here is utilized. Although cats, dogs, and even humans can eat many products, it is how we are able to utilize that product or its constituents that make it nutritious or not.
Many common health issues may be prevented or mitigated with a healthy diet. Conversely, a poor diet can have a deleterious impact on health. The study of nutrition addresses the metabolic and physiologic responses of the body to diet and is concerned with metabolism and metabolic pathways; the sequences of biochemical steps through which substances change from one form to another.
Carnivore and herbivore diets are opposite with basic nitrogen and carbon proportions at varying levels. Carnivores consume high nitrogen and lower carbon diets while herbivores consume lower nitrogen and higher carbon diets.
Much of the current nutritional recommendations for cats and dogs exists as mere minimums and maximums with no optimum level defined. Why is this? Scientists do not know what the optimum levels are. As research continues, the veterinarian and consumer must use their best judgments as to what constitutes an optimally nutritious diet. For more information on how these minimum and maximum levels are determined.