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Busting Myths about Cat Diet & Feeding

There are some common misunderstandings about feline diet and feeding so we asked animal nutritionist Shiva Greenhalgh from Sydney Animal Nutrition to separate facts from fiction based on the latest scientific research...

It may surprise you to learn that not all pet owners are aware that cat nutrition differs markedly from dog nutrition. But knowing there is a difference is not enough – and myths have circulated amongst pet owners and even in cat food marketing about these differences. 

For this article, we hope to illuminate the science to resolve these misunderstandings and aim to clarify issues covering diet, tuna and feeding frequency.

Cats: the obligate carnivores

A little bit about Evolution, Biology and Metabolism...

To better understand our modern domesticated feline friend, we need to understand their genesis. Domestication of the cat occurred approximately 10,000 years ago as a companion animal and to hunt pest species on our behalf. 

Unlike dogs (which were domesticated 16,000 years ago), cats have historically been less reliant on our food scraps which meant that they did not undergo the same level of biochemical, behavioural and genetic change. 

Changes in dogs meant that they could thrive on an omnivorous diet (i.e. feeding on food of both animal and plant origin), while cats maintained their ancestral diet as an ‘obligate carnivore’ (i.e. reliant solely on animal tissue) and sourced energy from meats, fish and other animal products.

The difference between the two is stark. Cats have protein requirements which are two to three times higher than an adult omnivorous species. 

Ancestral and wild cats survive on prey which they sense and capture, their canine teeth masticate (chew) rather than grind (as herbivores do) and possess short intestinal tracts with differing enzymes and gut flora suited to digesting animal-based protein. 

Unlike omnivores who derive most of their energy from carbohydrates, obligate carnivores use protein for maintenance of blood glucose concentrations even when sources of protein in the diet are limited. Cats can use carbohydrates as a source of metabolic energy but are limited in their ability to spare protein utilization by substitution of carbohydrates.

Fish: Tuna and Sardines

Fish based foods and treats are perhaps the most prolific in cat food sales and marketing. It is a commonly fed and provides an inexpensive source of protein that is very palatable. However, there is such thing as too much of a good thing. 

When feeding tuna for instance, most pet owners will opt for tuna in oil as opposed to spring water, mainly because of the enhanced flavour and texture that the oil provides and a belief that the oil is very beneficial for the cat.

However, tuna and sardines that are packed in oil contain high levels of polyunsaturated fatty acids (PUFAs). Tuna fed regularly leads to an excessive intake of PUFAs which can lead to vitamin E deficiency. An animal’s vitamin E requirement is directly affected by the level of unsaturated fatty acids present in the diet. Therefore, as the level of unsaturated fatty acids increase, the animal’s vitamin E requirement will also increase. 

When a cat is fed a food high in PUFAs, with no concomitant increase in vitamin E, their body fat is not sufficiently protected from oxidative degradation. This results in oxidative stress and the formation of peroxides and hydroperoxides. So why does this matter? 

Over time, this accumulation of reactive peroxides in adipose tissue leads to a condition ‘pansteatitis’. Pansteatitis (or yellow fat disease) is characterized by chronic inflammation and discoloration of body fat (Case et al, 2011). 

Clinical signs of pansteatitis in cats are:

✔️ Depression and anorexia
✔️ Sensitivity to touch of the chest and abdomen
✔️ Abnormal fat deposits under the skin and abdomen.

The prognosis of affected cats is very good, provided it is identified with appropriate intervention to reverse clinical signs. Such interventions include:

✔️ Dietary changes, however, this can be difficult if the cat is reluctant to eat other protein sources, with a preference for tuna and sardines.
✔️ Oral vitamin E (alpha-tocopherol), which is prescribed at 10-25IU twice daily until clinical signs resolve
✔️ Corticosteroid therapy (more severe cases).

In other words, remember all good things in moderation and next time you buy tuna for your cat, choose the spring water option.

Issues around feeding frequency

African wild cat (Felix Sylvestris) 

As an animal nutritionist, clients commonly have questions about the amount and frequency of feeding and there are some misunderstandings. One confusion stems from a common belief that the ancestral cat preyed upon large graze eating fauna, like that of the ancestral wolf which meant that cats were intermittent eaters. 

Credit: MpalaLive!
The ancestor of the domestic cat goes back to the small, desert dwelling African wild cat (Felix Sylvestris). 

Its primary prey was limited to small rodents. Rodents were more abundant, easier to prey on and were eaten more frequently throughout the day. 

This meant that the cat avoided the intermittent feeding that the ancestral wolf and larger wild cats experienced. The African wild cat, like most wild cats, lived a solitary life except for mating season.

This meant that unlike the wolf, eating rapidly due to competition was not a relevant factor. This behaviour has carried onto the domestic cat, with food being eaten more slowly and over the course of a day

In homes where there is more than one cat, an increase in the rate of eating or volume of food does not appear to occur. 

Therefore, given this evolutionary behaviour it is best to offer free-choice feeding

Arya's meals are scheduled for 7am and 4pm daily
but she never finishes her meal in one session
Photo: PetSafe Smart Feed Automatic Pet Feeder
This option always involves having surplus amount of food available.

The pet can consume as much food as desired at any time of the day. This type of feeding relies on the animal’s ability to self-regulate food intake so that energy and nutrient needs are met. This is best suited with dry food.

Meat and wet food would require a time limitation to avoid spoilage. With that said, it is important to acknowledge that there are concerns of overeating and obesity

The onus is then on the owner to ensure that they provide just a little over the energy requirements of their cat based on their food label instructions, as well encouraging enriching activities that involve good sessions of play and exercise. 

Whilst free-choice feeding is the most suited to the domestic cat, other feeding regimens can be adopted by some cats, and this can all depend on the individual cat. The science is also not fixed on this subject, with a recent study conducted in Canada by Camara et al (2020) suggesting that one meal a day was better for indoor cats as it may benefit them in increasing lean body mass and satiety. 

Whilst interesting, further research is needed with a significantly larger sample size (this study only used eight cats) and looking at more variables pertinent to their lifestyle.

We generally live our lives by conventional wisdom because generally accepted beliefs tend to ring true. However, this is not always the case. 

Common myths about cats have done harm to our feline friend and it is important for us to always be open to learning new things if we want to give them the happy and healthy lives they deserve.

written by Shiva Greenhalgh, February 2021 for Australian Cat Lover (all rights reserved).

About the writer

Shiva Greenhalgh is an animal nutritionist and owner of Sydney Animal Nutrition, which specialises in companion animal nutrition advice.

Shiva holds a Bachelor of Science (Zoology) from Western Sydney University and a Masters in Animal Science (Animal Nutrition) from the University of Sydney.
Shiva is also member of the Nutrition Society of Australia.
In her spare time Shiva volunteers for WIRES, educating the public on native wildlife.

Sydney Animal Nutrition services all of NSW, and can accommodate interstate pet owners. 
To have a chat about your pets' nutrition or to find out more, please visit

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