Protein can come from many sources including wheat (a plant). Although cat food may be high in protein it may be because it contains lots of wheat products. We know that cats are obligate – meaning strict – carnivores. The cat has evolved to get his nutritional needs through consumption of a large amount of animal proteins. Your cat obtains much less nutritional support from wheat proteins or indeed any plant-based proteins.
Firstly, cats lack ‘specific metabolic pathways’. This means they cannot utilize proteins derived from plants as efficiently as they can animal proteins.
As Dr Pierson DVM says, not all proteins are the same. It is quite technical but plant proteins do not contain the full number of amino acids required by the strictly carnivorous domestic cat.
Whereas dogs and people can make up, through their metabolism, the missing pieces of the amino acid profile that exists in plant protein, cats cannot do this. Although dogs are also carnivores they are not strict carnivores and some people say they are omnivores. Also humans can live on a vegetarian diet. We know that cats can’t despite the fact that a few people say they can. Indeed, a vegetarian diet for dogs is also not recommended.
Another important aspect of plant-based protein diet is that it is deficient in taurine (an organic acid). One of the most important nutrients present in meat is taurine. We know that taurine deficiency in a cat’s diet can cause serious illness. It can cause blindness and heart problems.
Dry food is often quite heavily plant-based. Is therefore not of the same quality in comparison with the protein in canned food which is meat-based. The protein in dry cat food is of lower biological value (BV – a measure of the proportion of protein from food that is absorbed by the body).
The pet food companies say that they know what is missing in plant-based proteins and therefore are able to add these missing elements to the cat’s diet to make it complete and balanced despite being based upon plant protein.
Apparently in 1980s, I suppose when the pet food industry was less sophisticated, cats were going blind and dying from heart problems due to taurine deficiency in the manufactured cat food.
It appears that initially, and I hope and believe that this has been rectified, manufacturers of pet food supplemented their taurine-deficient diet with synthetic taurine. Synthetic taurine is manufactured from a chemical reaction and it is produced in China. China has a very poor record with respect to products for the domestic cat. There have been some scandals.
The truth of the matter is that the pet food manufacturers are driven by profit which is something that we are all aware of. They are also arrogant enough to believe that they can artificially create the cat’s specialist diet by piecing together bits of a nutritional puzzle rather than going back to basics and simply manufacturing cat food from meat.
Beware of trying to compare dry and wet food ingredients and nutritional values. It takes some math (maths) to work out a true comparison. In addition biological values are not being compared.
Note: My thanks to Catsinfo.org and Dr Pierson for guiding me.