feline nutrition
What is healthy cat food
Cats are biologically wired to get necessary nutrients from prey. High-quality meat sources are important for optimal health of a feline.
If you’d like to know what to feed your cat, click here, if you want to know why, keep reading.
Obligate carnivores
Cats are obligate carnivores, it means, that they require meat to survive and that is why they are much less adaptable than omnivores, who can survive feeding on a wide variety of plant and animal sources.

The difference between obligate carnivores (e.g. cats, eagles, snakes) and omnivores (e.g. dogs, bears, humans) is that the latter are able to synthesize a variety of nutrients from both plant and animal sources, while obligate carnivores lack this ability and the only way for them to get many of the required nutrients is directly from the food that contains them. For example, Guidi in her book “Canine And Feline Nutrition And Dietetics” (2020) writes, that dogs synthesize vitamin A from b-carotene (found in carrots, sweet potatoes and dark green vegetables), while in cats the enzyme necessary for such synthesis is either strongly deficient or absent and the only way for them to get an adequate amount of vitamin A is to eat animal sources that contain it.

Another crucial difference between cats and dogs is that cats are not able to digest carbohydrates as efficiently as dogs do as “cats do not have salivary amylase and they have lower amounts of pancreatic amylase than dogs” (Guidi, 2020).
“…the natural diet of dogs, and above all, the diet of cats, is low in carbohydrates and rich in proteins. Cats do not have salivary amylase and they have lower amounts of pancreatic amylase than dogs…”
— Debora Guidi
There’re many metabolic peculiarities that cat have that show their predisposition to a carnivorous diet. To name a few, cats are unable to synthesize:
  • vitamin D (found in fish, liver, beef, egg yolks, etc.);
  • niacin (poultry, fish, beef, etc.);
  • adequate amounts of taurine (although it is present in many animal protein sources, such a chicken, turkey, fish, all commercial foods are required to have extra taurine added; here is why);
  • citrulline (but they can convert arginine to citrulline, as a result, a single arginine-free but protein-containing meal can cause death);
  • arachidonic acid (found in poultry, animal organs and meat, fish, seafood, eggs);
therefore, all of these nutrients must come from the food they eat.
Cats have low tolerance for glutamic acid (which is high in plants and low in animal tissues). Excess amounts cause sporadic vomiting and thiamin (B1) deficiency.

Because cats have a reduced ability to conserve nitrogen, high (in vitro) activity of enzymes that break down protein and a limited ability to adjust protein oxidation to low consumption of dietary protein (meaning, their body will use protein, if not from food, then from their own muscles and organs), they need to consume at least the minimum required amount of protein regularly, otherwise they will start to lose weight and show other signs of amino acid deficiency (see pic. 1.2).

Pic. 1.2.

Cats’ natural diet is high in protein, moderate to high in fat, and low in carbohydrates. Cat are adapted to high levels of protein and use it for maintenance of body functions and as an energy source.

But having a high-protein diet doesn’t mean eating only muscle meat. Cats benefit from some carbohydrates in the diet, fats are necessary, and so is fiber. Organs are important source of animal fat, vitamins and minerals.

A balanced and healthy diet includes bioavailable protein sources, fats, fermentable fiber and supplements (vitamins are added to compensate for their loss during heat processing of meat; minerals; taurine). Therefore, just feeding muscle meat means there is too much protein and not enough other necessary nutrients.
Cats cannot adapt to lower than required minimum amount of protein in their diet, which means that if the food doesn’t contain enough bioavailable protein, they will either over-eat trying to get the required minimum (and end up getting lots of carbohydrates in the process) or their body will use the proteins from their own muscles and organs.
What about all the grains?
NO-GRAIN is pretty popular. Let’s find out what it means and if it’s better.
How much protein and fat is in the mouse?
Most importantly, it’s necessary to understand that cats are capable of digesting some amount of grains if they are processed correctly. More than 10% in the diet of a healthy cat is unnecessary (nursing and pregnant cat can get up to 20% due to high energy consumption during these periods).

Simple carbohydrates are digested fast and raise blood glucose rapidly. It takes a cat 4 hours to get their blood glucose back to the baseline. In comparison, it only takes 1.5 hour for a dog.

In many commercial diets (even super premium ones) the amount of grains well exceeds 10%, as grains are a cheap source of energy and plant protein (plant protein is not complete and balanced for cats).

Corn is often used in cat food as a source of carbohydrates, it is very cheap, but it is highly prone to mold infestation. Grains that are generally a better choice are rice (if prepared correctly is easy to digest for cats), buckwheat or quinoa.

So if a food doesn’t contain any grains, does it mean it’s more biologically appropriate? Not really. Often no-grain cat food will still have a high carbohydrate content. Cat food manufacturers may use potatoes instead of grains.

So, if you want to feed your cat a more biologically appropriate diet, you will choose one where not more than 20% of calories come from carbohydrates, be it grains or other sources.
  1. Canine and Feline Nutrition and Dietetics: A Guide for the General Practitioner by Debora Guidi, 2020
  2. Canine and Feline Nutrition by Linda P. Case, 2010
  3. Applied Veterinary Clinical Nutrition. Editors: Andrea J. Fascetti, Sean J. Delaney, 2012
  4. Small Animal Microbiomes and Nutrition by R. Saar, S. Dodd, 2024

DISCLAIMER: the content of this article is for informational purposes only and not intended to be a substitute for professional advice, diagnosis, or treatment of a veterinarian or veterinary dietician/nutritionist. The content of this anrticles is not intended to be a substitute for individualised professional veterinary advice, diagnosis, or treatment, and reliance should not be placed on it. For personalised veterinary or cat nutrition advice, users should make an appointment with their a qualified pet health care professional. We strongly recommend consulting with a veterinarian/veterinary dietitian/board certified veterinary nutritionist before introducing any new products to your pet's diet, especially if your pet has any known or suspected allergies or dietary restrictions. Each cat’s health is unique, and their nutrition should be tailored to their specific needs.


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