The domestic cat (Felis catus) is descended from the African wildcat (Felis sylvestris lybica), and remains extremely closely related and very similar to this species in size, shape, behaviour and physiology.
Like all cats, the domestic cat is a carnivore (primarily a meat eater) and is adapted to a hunting lifestyle. In fact, cats are extremely well adapted predators and they not only eat meat, but in fact they have become dependent on a meat diet (they are obligate carnivores) and actually cannot thrive or survive without meat in their diet.
This is a simple and understandable adaptation for a hunting animal like the cat – there is no need for them to have special enzymes or metabolic pathways to digest and convert nutrients in plants to what they need, when it is present already in the animals they prey on!
However, this adaptation to become strict carnivores means that cats have a number of special dietary requirements that do not apply to many other animals (humans and dogs for example), and it means that feeding a proper balanced diet to a cat can be much more challenging.
Palatability of foods
The factors that influence palatability of food for cats are complex, but include texture, odour, taste, and temperature.
The smell, or odour, of food is particularly important and cats have an extremely well developed sense of smell. This is also enhanced when food is slightly warmed, so cats actually prefer food that is around body temperature (around 35°C). The senses of taste and smell combine to give the perception of the flavour of a food, and for cats foods that have a high level of protein and fat in general are much more palatable. While cats can taste substances that are salty, sour or bitter, unlike humans and dogs they are not able to perceive sweet tastes. Again, this is a simple adaptation of an animal that is dependent on meat rather then plants for its survival. The texture of food is also important and in general cats prefer the texture of meat.
Although we know what type of foods cats generally find most palatable, there is considerable variation between individuals. Some of this is simply as a result of food experiences early in life – kittens will tend to eat and like the same foods that they see their mother eating and may develop a strong preference for this. Additionally, some cats will develop a strong preference for a particular type of food (eg, wet/tinned food or dry food) when fed over a prolonged period of time. Nevertheless, most cats are inherently 'neophilic', meaning that they like to explore and try new and different foods and enjoy variety.
Frequency of feeding
Under natural circumstances cats hunt and consume their prey throughout the day, consuming frequent small meals. Domestic cats will also tend to eat this way given the choice – rather than eating one or two 'main meals' each day they prefer to have many small meals.
Other factors will also affect the feeding pattern of cats though, including what they become used to, lighting and noise levels, presence of other cats etc. Cats prefer to eat from shallow bowls so that they can see around them at the same time as eating and so their whiskers are not brushing against the sides of the bowl. Also, it is better to feed cats from a glass or ceramic bowl rather than a plastic bowl as plastic bowls can pick up odours (which may be unpleasant and become tainted).
Stress can have a profound effect on feeding – cats will be much less likely to eat when stressed and will be much less willing to try any new or different foods. This can be of significance, for example, when a cat is hospitalised in a veterinary clinic – this is inevitably associated with some stress and offering the cat’s normal food rather than something new or different is likely to be more successful.
Energy needs in cats and obesity
Most cats have an inherent ability to control their energy intake well and avoid becoming overweight or obese. However, the self-regulatory mechanism is often interfered with in pet cats in a number of ways. Feeding very highly palatable foods may lead to excessive food intake, and having a ready supply of food provided for a pet cat means that they have to expend very little energy in acquiring their food (unlike the situation in the wild!). Additionally, most pet cats are neutered, and while this has many health and welfare benefits for the cat it does interfere with their natural ability to regulate calorie intake and they will tend to consume more than is required.
For these reasons, it is important to try to control your cat's food intake and avoid them becoming overweight. As in humans, all cats are individuals and have differing requirements to maintain their normal weight. Follow the instruction on the food packet/sachet/tin as an initial starting point, but adjust the daily amount up or down as necessary to keep your cat in peak condition. If using a dry food, ideally weight the food each day rather than using a measuring cup – this is a much more accurate way of making sure you are feeding the right amount.
It will help to divide your cats food into several small meals and, especially is using dry food, these can be hidden in different places around the house, or you can use 'feeding puzzles' to provide your cat with some interest and fun in tracking down and finding their food.
See obesity in cats.
Important nutrients for cats
Because cats are obligate carnivores (see above), they have some very different dietary requirements compared with dogs and humans – some of these are outlined below.
Proteins are large complex molecules consisting of chains of smaller building blocks called amino acids. Cats, like all animals, require protein in their diet to provide for their needs. However, while humans and dogs can adapt to diets that have a relatively low protein content (eg, plant-based diets), cats have a much higher protein requirement in their diet that would typically only be met by feeding a meat-based diet.
In addition to requiring a much higher level of protein in the diet, cats also require a number of specific amino acids to be present – these include taurine, arginine, methionine, tyrosine etc). Without some of these amino acids in the diet, cats will simply die. These amino acids are not found in plants – many animals (including dogs and humans) can convert and use other amino acids derived from plants, but for cats they need a preformed source of these amino acids in protein from an animal source.
Fat in the diet is a good source of energy, but also supplies fat soluble vitamins (A, D and E), enhances the palatability of food, and is a source of a type of fat called essential fatty acids (EFAs). These EFAs play key roles in maintaining the health of animals being vital in many metabolic pathways and for the integrity of the skin. Many animals like dogs and humans can convert EFAs found in plants into the EFAs that are needed in the body, but again cats require a source of animal fat with preformed animal-origin EFAs as they cannot meet their needs from plant sources.
Cats do not actually need a source of carbohydrate in their diet, and a natural diet for a cat tends to be low in carbohydrates. In contrast to many other animals, cats will derive most of their blood sugar from the breakdown of protein in the diet rather than carbohydrates. However, this does not mean that cats cannot use carbohydrate or that it should not be present in the diet, but as they have a more limited capacity to digest and utilise carbohydrates diets need to be formulated carefully.
Apart from kittens, most cats have low levels of the enzyme lactase in their intestine. This is the enzyme needed to digest the major carbohydrate (lactose) present in milk. For this reason, consumption of ordinary milk, and especially in high quantities, can often lead to diarrhoea in cats.
Again, in keeping with their adaptation to a strict meat diet, cats require preformed vitamins in their diet that are present in animals but not in plants – these include vitamin A, vitamin D and vitamin B3. However, while cats require a source of these in their diet, conversely too much of some of these vitamins can also cause problems.
Although cats clearly need meat in their diet, it is also wrong to think that they only need a source of meat. Sometimes kittens are fed a meat-only diet as they grow up, using fresh cooked meat such as chicken. Although this meets many of their dietary requirements, some critical components are still missing. It is important to remember that in the wild cats would eat a whole animal carcase (meat, organs and bones) and if fed only the meat this, among other things, is highly deficient in minerals such as calcium and will not allow the bones to grow properly.
Because kittens are growing at such a fast rate, they have higher nutritional demands than adult cats. It is usually possible to start weaning kittens from around 3-4 weeks of age at which time small amounts of a good quality kitten food can be offered. It is usually best to start with a wet (tinned) kitten food, or to soak some dry kibbles designed for kittens in water to thoroughly moisten them. As kittens grow and develop they can be transitioned to dry food if preferred. Weaning is usually completed by around 8 weeks of age.
Choosing a cat food
Because of their unique and special dietary requirements, it is actually extremely difficult to provide a good balanced diet for cats with home-prepared foods. Feeding a good quality commercial cat food (tins, sachets or dry food) is therefore preferable, at least as the major part of the diet and cats should never be fed dog food.
Offering different foods with different flavours and textures can be good for cats, and feeding small frequent meals along with hiding food in different places provides some fun and challenge for a cat. Good quality dry and tinned/sachet foods are both suitable to be fed to cats, but in some situations (especially some medical conditions) it may be important maximise a cat’s water intake, and where this is needed, feeding a wet or sachet food is better.