This is a common question posed to
veterinarians. I just finished reading an excellent newsletter from Drs. Wackerbarth and
Vaughan at the Hyperthyroid Treatment Center in
We need to always remember that
cats are obligate carnivores. This means
that they rely on the nutrients in animal tissues to meet their nutritional
needs. In the wild, a prey diet
consisted of 50-70% protein, 30-50% fat
and less than 2% carbohydrates. A
significant portion of their water needs were also met from their diet. Cats are designed to use proteins and fats as
energy, so they need a lot of protein in their diet. When omnivores like dogs and humans ingest
insufficient protein, they can conserve amino acids and use carbohydrates for
energy. Cats cannot switch from protein
use. When their diet is deficient in
protein, they will burn their own muscle tissue for energy.
Cats also have specific amino acids
that must be in their diet. Cats don’t
have the ability to synthesize arginine, cysteine, methionine, and
taurine. They must eat meat based
proteins so they have the full complement of amino acids carnivores
require. Plant based proteins found in
higher levels in dry foods are of low biological value for cats for this
reason.
Feline metabolism lacks many of the
enzymes and pathways needed to utilize carbohydrates. They can’t store their glucose like omnivores,
so they are more hyperglycemic after a meal and carbs that aren’t used are
stored as fat. Cats on higher
carbohydrate diets are more prone to diabetes and obesity.
Fats provide energy and are
responsible for a diets palatability.
Meat based diets with animal fat provide appropriate fatty acids and
needed hormone precursors.
Animal proteins are more expensive
than virtually any other ingredient in pet food. Many canned and all dry foods include plant
based proteins and not enough meat.
Whole grains, glutens, and soy are of low biologic value to the
cat. Remember that “grain-free” does not
equal “carb-free”. Potatoes, peas and
soy are all “grain-free”.
Canned foods are energy dense
foods. This is great for thin cats but can
lead to weight gain. So in heavier cats,
portion control becomes more important.
So, what should we feed our older
cats?
On a dry matter basis, 40%+ meat
based proteins, about 50% fat, and less than 10% carbohydrates. {The Feline Nutrition Awareness Effort website has an
explanation of Dry matter basis and a calculator so foods can be compared
accurately. http://fnae.org/dmb.html}
Any canned food is better than any dry food. High quality canned foods with high levels of
animal based proteins that contain little to no fruits, vegetables, or grains
are the best choice.
Timothy R Kraabel, DVM, DABVP (Canine/Feline Practice)
Outreach Chairman, American Board of Veterinary Practitioners
