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Feeding cats, as obligate carnivores

Cats are obligate carnivores, which is as an animal that must eat animal meat and organs to meet their nutritional needs.   Wild cats and domestic cats in a natural habitat will hunt and consume prey animals, which are high in protein, with moderate amounts of fat and minimal amounts of carbohydrates.  They may eat other foods, such as fruits, honey, grains, and so forth to fulfil their need for other nutrients, however they lack the physiology required for the efficient digestion of vegetable matter.  Cats do not produce salivary amylase, and thus have little taste perception for carbohydrates.  Rather than sugar, cats are attracted to the taste of animal fat and proteins (in particular the amino acids alanine, proline, lysine and histidine). 


Cats have a higher protein requirement than dogs as they derive energy entirely from amino acids derived from consumed protein (gluconeogenesis).  This is unlike omnivores and herbivores that can derive energy from starch in their food and metabolically derived glycogenic amino acids. Whilst the pancreas of the cat does secrete amylase, and cats are able to digest starch and absorb glucose in the small intestine, this cannot maintain the blood glucose of cats.  Cats also have a higher requirement for dietary nitrogen than any other mammal.   As cats cannot conserve nitrogen in a nitrogen pool, and their liver is permanently set to process high levels of protein, they require a constant dietary intake of meat protein in order to derive adequate levels of nitrogen (Wortinger, 2007).


Of the 22 amino acids, there are 11 essential amino acids which must be provided in the diet of cats as they cannot be synthesised by the body in sufficient quantities. These are taurine, arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.  Unlike dogs and humans, taurine is essential for cats and the best sources of taurine are animal protein sources, in particular the organs (e.g. heart, kidney, liver).


Feline Feeding Behaviours:


Cats are obligate carnivores and their diets and feeding behaviours closely resemble their ancestor, the Felis silvestris libyca, a small African wildcat normally found in desert environments.  The wildcat hunts and consumes multiple small prey throughout the course of the day, particularly in the early morning and evening.  Like their wild ancestors, and other carnivores, the feeding behaviours of the domestic cat include searching, hunting, and catching of prey, with postprandial grooming and sleeping.  Unlike the dog, cats are lone hunters and due to the size of their prey, will eat small meals frequently.   The wildcat will eat on average 10 to 20 meals per day, and the meal amount is approximately the same size and caloric value as a mouse at around 30g and 23kcal (Wortinger, 2007).  To reach their daily calorie requirement, cats must hunt continuously throughout the day.  A feral cat’s diet is comprised largely of small rodents (40% of the diet), with the remainder being small rabbits, insects, frogs, lizards, and birds.  Large wildcats, such as lions and tigers, have different feeding behaviours and tend to eat larger prey and eat less frequently.   




As a desert animal, cats are designed to obtain most of their water from their dietary intake rather than from drinking water.  Their wild ancestor consumes a prey diet, which contains approximately 70 to 75 percent water.  Dry kibble only contain less than 10 percent water.  Wet cat food contains approximately 78 percent water.  Thus, wet/canned food more closely approximates the natural diet of cats and can better meet their moisture needs (Pierson, 2013). 

Feeding schedules for domestic cats?


In a domestic setting, set feeding times can be harder to maintain for cats than it is for dogs. Of the three feeding regimes, most cat owners feed their cats ad libitum with dry biscuits.  Feeding cats dry biscuits is problematic and can lead to dehydration due to their low thirst drive.  Domestic cats, like their wild ancestors, derive approximately 80% of their moisture requirements from their prey, as meat is high in water content.  Modern cats have retained their evolutionary adaptions to a desert environment and have a decreased thirst drive, low water intake, and produce highly concentrated urine (Wortinger, 2007).


Cat owners often struggle to get their cat to eat larger portions of wet food or raw food in one sitting. The risk of contamination from leaving raw or wet food out for prolonged periods of time is an important food hygiene issue, affecting animals and humans in the household alike.   Timed feeding with cats can sometimes require consistent training to set in place. Timed feeding twice to three times a day with portion-controlled meals allows the amount of calories the cat is consuming per day to be monitored and maintained consistently.


Cats can be very picky with their food, as they have very well developed olfactory senses, which make them sensitive to the texture, odour, and taste of their food.  This is why even a minute change in their diet can cause cats to refuse their food. Cats will typically start to eat their live caught prey from the head, and the direction of the hair growth and thus the texture of the food will dictate this preference (Wortinger, 2007).  The temperature of their food can also be a factor, as cats usually like to eat their food at around 38 degrees Celsius, which is the typical body temperature of freshly killed prey. 


The predatory drive of the cat is very strong, and they will even stop eating to make another kill to optimize their food availability.  This drive can be stimulated in a domestic cat by providing enrichment through interactive toys and food puzzles so they can express this natural behaviour. A lack of stimulation can cause boredom, destructive behaviour, and anxiety.

ZIWI cat food

ZIWI Peak cat food offers a perfect solution for feeding domestic cats: 

  1. All ZIWI recipes are rich in animal protein & organ meat offering the correct nutrient and amino acid profile for an obligate carnivore

  2. Ziwi is highly digestible, with a digestibility rating of 95.6% (Massey University, NZ)

  3. All ZIWI recipes are complete and balanced to AAFCO standards

  4. ZIWI canned food contains moisture, which is a species appropriate way to address their daily water needs

  5. No ZIWI recipes contain grains, potatoes or sugars


Pierson, LA 2013, “Feeding Your Cat: Know the Basics of Feline Nutrition”,

Wortinger, A 2007, “Nutrition for Veterinary Technicians and Nurses”, Blackwell Publishing Professional, Iowa.

Review: Debra Zoran's article on cats as obligate carnivores and diet

Debra Zoran published an excellent article in the Journal of the American Veterinary Medical Association explaining what it means metabolically and nutritionally for cats to be an obligate carnivore.

She explains:

  • Cats are obligate carnivores that rely on nutrients in animal tissues to meet their specific and unique nutritional requirements.

  • In their natural habitat, cats consume prey high in protein with moderate amounts of fat and minimal amounts of carbohydrates.  They are metabolically adapted for higher metabolism of proteins and lower utilisation of starch than dogs or omnivores.   Cats can use carbohydrates as a source of metabolic energy, they have limited ability to spare protein utilisation by using carbohydrates instead. 

  • In spite of this, commercial diets are formulated with a mixture of animal and plant derived nutrients, most commonly in dry kibble form that requires carbohydrates for the expansion and cooking process.


  • Cats are metabolically adapted to preferentially use protein and fat as energy sources.

  • This evolutionary difference in energy metabolism mandates cats to use protein for maintenance of blood glucose concentrations even when sources of protein in the diet are limiting.

  • Adult cats require 2 to 3 times more protein in their diet than adults of omnivorous species.

  • Cats have an increased need for dispensable protein

    • Cat nutrition studies show that cats continue to use protein (eg, dispensable nitrogen in the form of gluconeogenic amino acids) for production of energy and in other metabolic pathways (eg. urea cycle), even in the face of low availability of proteins.


  • Cats also have a need for increased amounts of specific amino acids in their diet:  taurine, arginine, methionine, and cysteine.  Cats neither have the ability to synthesize these amino acids, nor are the amino acids conserved in their bodies. In fact, utilization of these amino acids (taurine, arginine, methionine, and cysteine) is higher in cats than in dogs or other animals.  It is likely that they have not developed mechanisms to conserve them due to the abundance available in their natural diet



  • Cats lack salivary amylase, the enzyme responsible for initiating carbohydrate digestion

  • Cats have low activities of intestinal and pancreatic amylase and reduced activities of intestinal disaccharides that break down carbohydrates in the small intestines.


  • Cats can use starch efficiently BUT as carnivores, high amounts of carbohydrates in the diet may have negative effects on their health


  • decrease protein digestibility in cats


  • cause a reduction in faecal pH in cats (due to incomplete carbohydrate fermentation in the small intestine that results in increased microbial fermentation in the colon and increased production of organic acids).


Cats' hepatic function is different!

The liver of the cat has several distinct features that influence disaccharide metabolism:

  • Cats have minimal function of hepatic glucokinase, and the activity is not adaptive (i.e. cannot be upregulated when the diet contains large amounts of carbohydrates)
  • Cats have minimal activity of hepatic glycogen synthetase (the enzyme responsible for converting glucose to glycogen for storage in the liver).

  • Cats have limited ability to rapidly minimise hyperglycaemia from a large dietary glucose load.

  • The liver in cats does not contain fructokinase, an enzyme necessary for metabolism of simple sugars.

  • Cats are not attracted to foods with a sweet taste.  Cats prefer foods flavoured with animal products (eg fats, meats).




  • Meat based diets supply essential fatty acids to cats, including linoleic, linolenic, arachidonic acid, and some eicosotrienoic acid. 

  • Unlike other animals, cats lack adequate hepatic alpha-6-desaturase activity and other hepatic desaturases, all of which are required for syntheiss of arachidonic acid and eicosapentaenote and docosahexaenoate.

  • Cats do not have the enzymatic machinery to synthesise derivatives of arachidonic acid.



The vitamin needs of cats are unique:

  • Cats require increased amounts of dietary water soluble B vitamins  including thiamine, niacin, pyridoxine (B6) and cobalamin(B12). Pyridoxine is especially important as it is an essential co-factor in all transaminase reactions , which are constantly active in cats due to their reliance of protein for energy as well as building and synthetic functions.  Since most water soluble B vitamins are not stored, except cobalamin, which is stored in the liver, a continual dietary source is required.

  • Cats cannot convert beta-carotene to retinol, the active form of vitamin A, thus the biologically active form must be obtained from the diet – from animal tissue.

  • Cats lack the enzyme to allow dermal synthesis of Vitamin D. Vitamin D is found in high levels in fat and liver tissue – thus needs are normally met from the natural diet.



  • Cats have a less sensitive response to thirst and dehydration than dogs and other omnivores. This reflects their development as desert animals and as strict carnivores, which obtain most of their water requirements from their prey.

  • In older cats which produce urine with a lower SG, an increase in water consumption is very important to prevent dehydration and the development of a pre-renal azotaemia

Reference: Zoran, DL 2002, ‘The carnivore connection to nutrition in cats’, Journal of the American Veterinary Medical Association, vol. 221, no. 11, pp. 1559-67.

See also Dr Richard Malik 2007, "Feeding cats for health and longevity – an idiosyncratic perspective", Australian College of Veterinary Scientists – Science Week 2007 – Small Animal Medicine Chapter meeting

Is there any research?

Are there any studies supporting a natural diet approach to feeding cats? Yes there are! Click below to read summaries of nutrition studies in cats.

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