A substantial share of the protein in dry cat food is frequently plant-based. Here’s the problem: Plant based proteins have a lower biological value to obligate carnivores than meat proteins. For pet food manufacturers, obviously, plant proteins cost less because corn, soy, rice, and wheat are less expensive to source than meat.
When you’re reading the label on a cat food, it’s important not only to notice the percentage of protein, but to know the source of that protein. Do the formulators of pet food have the wisdom to make up for what may be missing by using so many species-inappropriate ingredients in cat food? Dr. Lisa Pierson of CatInfo.org puts it this way:
Veterinary nutritionists and pet food company representatives will argue that they are smart enough to know *exactly* what is missing from a plant in terms of nutrient forms and amounts – nutrients that would otherwise be in a meat-based diet. They will then claim that these missing elements are added to their diets to make it complete and balanced to sustain life in an obligate carnivore.
The problem with this way of thinking is that humans are simply not that smart and made fatal errors in the past when trying to guess how to compensate for such a drastic deviation from nature. Not all that long ago (the 1980s) cats were going blind and dying from heart problems due to Man’s arrogance. We learned in the late 1980s that cats are exquisitely sensitive to taurine deficiency and our cats were paying dearly for straying so far from nature in order to increase the profit margin of the pet food manufacturers.
There are several situations that can lead to a diet being deficient in taurine but one of them is using a diet that relies heavily on plants (grains, etc.) as its source of protein. Instead of lowering their profit margin and going back to nature by adding more meat to the diets, the pet food companies simply started supplementing their diets with synthetic taurine.