Unlike wild lions, which take a variety of prey and eat most parts of it therefore ensuring a balanced diet, the domestic cat relies heavily on food provided by humans.
Like all animals, the domestic cat needs a diet that is properly balanced and contains all the essential nutrients in the correct quantities. These nutrients are water, protein, fat, carbohydrate, minerals and vitamins.
The wild members of the cat family (Felidae), such as the lion, tiger, cheetah and European wild cat, are carnivores. Between them they hunt and kill a wide variety of other animals, ranging in size from small lizards and birds to large antelopes. They don’t just eat the meat or muscle, but consume all, or almost all, of their prey, including the skin, hair or feathers, and the internal organs such as liver, kidney and intestine. Their diet therefore contains a substantial amount of animal protein, and supplies them with all the other essential nutrients that they require.
To remain healthy, domestic cats also require a diet containing animal protein. This is because they need a particular amino acid (one of the building blocks of protein) called taurine, which helps to prevent heart and eye disease. Taurine is plentiful in animal protein but only present in small amounts in plant protein.
While dogs are able to manufacture the amino acid taurine within their body, cats can only manufacture a little, and it is not enough to meet their needs, and plant protein cannot supply them with enough to make up the shortfall. Therefore although a pet dog could remain healthy if fed a properly balanced vegetarian diet, a cat could not.
For this reason cats are known as obligatory carnivores; they must eat some animal protein in order to survive.
This is the most important element in a cat’s diet. Whereas an animal can survive after losing half of its protein and storage fat, even a 10 per cent loss of total body water causes serious illness, and a 15 per cent loss causes death.
Animals obtain water in three ways. They drink it, eat food that contains it, and their body manufactures some water during the chemical processes involved when converting proteins, fats and carbohydrates into energy.
The daily amount of water required by a cat is roughly the same amount (in millilitres) as its energy requirement (in kilocalories) (see the table on p47). A sedentary cat needs a daily intake of about 65–70 ml (roughly four tablespoons) water for each kilogram (2.2 lb) of body weight, while an active cat needs about 85 ml (roughly six tablespoons).
This leopard will maintain healthy teeth and gums by chewing on flesh and bone. Domestic cats also need to chew to maintain dental health, which is an important consideration when planning your cat’s diet.
Protein occurs in animals (animal protein) and in plants (plant protein). There are many different types of protein, each of which contains a particular combination of amino acids, the substances that provide the materials needed for the growth and repair of all body tissues.
Proteins vary in their digestibility. The most digestible are those contained in foods derived from animal sources, such as meat, eggs and cheese. The least digestible are those contained in foods derived from plants, such as grains and vegetables. Most domestic cats consume a diet containing a significant amount of animal protein. They do eat some plant material, either in the stomach and intestines of prey that they catch, or by voluntarily eating specific plants such as grass, but plant protein is a comparatively unimportant part of the domestic cat’s diet.
When a cat eats grass it is probably doing so to consume fibre and as an aid to digestion. Quite often a cat will vomit soon afterwards, bringing up a bolus of grass mixed with mucus, so eating grass may be a useful method of getting rid of excess mucus from the cat’s stomach.
Fats and oils contain substances called fatty acids, some of which play an important role in helping to maintain certain internal body functions and a healthy skin. They also act as carriers for the fat-soluble vitamins (A, D, E and K). Fats are a concentrated form of energy (for a given weight, fat provides more than twice as many kilocalories as carbohydrate or protein).
If the diet that a cat consumes contains more energy than the cat needs, the excess is converted into fat that is stored in various parts of the body, such as under the skin and around the intestines. This stored fat acts as a fuel store that can be drawn upon in times of need.
These occur in plants and include sugars, starch and cellulose. There are various types of sugars, among which are sucrose and glucose, two of the simplest sugars and therefore more easily digested. Cow’s milk contains the milk sugar lactose, but many adult cats are unable to properly digest lactose – for this reason specially formulated lactose-reduced or lactose-free cat milk is available from pet food stores and supermarkets. For cats, one of the most useful sources of dietary carbohydrate is rice.
Like other animals, the cat needs to consume many different minerals to ensure that its body processes function normally. Some are required in comparatively large amounts, while others, known as trace elements, are only required in very small quantities. Two of the most important are calcium and phosphorus, involved in the formation and growth of bones and teeth. Minerals play an important role in the growth and repair of body tissues such as muscles, ligaments, skin and hair, the formation of red and white blood cells, and in various digestive processes.
Certain vitamins are essential for the proper working of body processes. Four of them, vitamins A, D, E and K, are soluble in fat, so fats and oils provide a good dietary source. Vitamins A and D play a particularly important role in bone growth. Vitamin E plays an important role in normal muscle function, vision and reproductive processes. Vitamins of the B-group, and vitamin C, are soluble in water. The B-group vitamins have a variety of functions associated with the metabolism of amino acids, fats or carbohydrates. Vitamin C is involved in wound healing, preventing haemorrhages from small blood vessels (capillaries) and maintaining healthy skin (preventing scurvy). Cats, like dogs, can manufacture this vitamin within their body, and unlike humans, they don’t need a source of vitamin C in their diet.
Derived from plant materials (often eaten along with prey), fibre does not provide a cat with any nutrients but it does play a very important role in digestion. It acts as a bulking agent, absorbs any toxic by-products of the digestive processes, and increases the rate of passage of food through the gut.
Energy is measured in kilocalories. It is not classified as a nutrient, but is the ‘fuel’ that a cat derives from the protein, fat and carbohydrate that it eats. Cats require sufficient kilo-calories to fulfil their basic energy needs, and this amount varies according to their size and circumstances. Adult cats do not have such a great range of sizes and weights as adult dogs. There are variations between breeds and individuals, but most adult domestic cats weigh between 2.5 kg (5.5 lb) and 5.5 kg (10 lb). Sedentary house cats need less energy than active cats that spend a lot of time out of doors. Energy use also varies according to environmental temperature, being greater in very cold temperatures or in hot tropical climates. Comparatively more energy is required per kilo-gram of body weight by a queen in late pregnancy and during lactation, by a kitten when growing, and by any cat during illness or stress.
Most cats are disciplined eaters and will eat little, often. Some cats, however, will eat all the food in their bowls, no matter how much it might be. Owners of such cats need to monitor their pets’ energy intake, or the cat may soon become obese.
Given the opportunity (for example, self-feeding on dry pet food and/or freedom to hunt), some cats will feed little and often, exercise themselves and remain within a satisfactory weight range. Others will eat everything on offer, and if their owner does not monitor their energy intake they will quickly become obese.
A guide to energy requirements for cats
APPROXIMATE DAILY ENERGY NEED Kilocalories per kg (2.2 lb)
Gestation (last 3 weeks)
140–170 (depending on the number of kittens in the litter)
Growth (weaning to 6 months)
Growth (6–12 months)
It is not unusual for domestic cats to put on weight in autumn and winter and lose it again in the summer. This probably reflects the situation in the wild, where many animals lay down a store of fat prior to winter when food becomes scarcer. When cats put on excessive weight and keep it on, it is usually the result of overeating or lack of exercise, or a combination of both. In this case their energy intake should be strictly monitored, because overweight cats, like overweight humans, are more likely to have health problems.
Commercial or home-cooked food?
Fast foods are as readily available for cats as they are for humans. Take a walk around any supermarket and you will see a vast array of canned, packaged or frozen options. There are foods for kittens, for adult cats and for mature cats. Many pet stores and veterinary clinics sell various ‘professional formulae’, some for ordinary maintenance and others for specific health problems.
When deciding whether to feed your cat a commercial diet or cook your own meals, there are various factors to consider. Many commercial diets are complete and balanced, which means that they will provide all the nutrients your cat needs. There is less certainty, though, that a homemade diet will be properly balanced.
You may also need to consider costs and convenience. Many commercial diets are more expensive than home-cooked ones, but home-cooked diets involve time, careful planning, preparation and storage.
Most cat owners find it convenient to feed reputable commercial diets and, if they wish, offer homemade ‘treats’ from time to time.
Pregnant queens, kittens, young growing cats and geriatric cats all have special dietary needs, so it is best to feed these a commercial diet specially formulated for their situation. Offer the occasional homemade meal to ring the changes.
Many commercial diets are formulated to provide all your cat’s nutritional requirements. They are formulated by nutritional scientists and veterinarians and have been tried and tested in controlled feeding trials and meet approved international standards.
There is a bewildering choice of commercial cat food. There are ‘mainstream’ foods, comparatively cheap, for the ‘average’ cat. There are ‘premium’ foods, often packaged in small quantities, that appeal to the human eye (and sometimes, but not always, to the cat’s taste buds) and are more expensive. Your cat can have a choice of lamb, beef, chicken, tuna, sardines or ocean fish, to name but a few. Some foods contain combinations, such as beef and chicken. The nutritional profile of all these foods is very similar; it is just the contents that vary.
Like their human ‘owners’, cats love to eat, although unlike humans they are able to lose up to 40 per cent of their body weight without losing their lives.
Commercial cat diets can be grouped according to their moisture content:
ο Canned or moist foods. These have a moisture content of around 78 per cent (roughly the same as fresh meat) and do not need preservatives because cooking destroys all bacteria and the canning prevents any further contamination. Because they contain no preservatives, if they are not used immediately after opening they require refrigeration.
ο Semi-moist foods. These have a moisture content of around 30 per cent and normally contain preservatives. Some do not require refrigeration. They are commonly fed as ‘treats’.
ο Dry foods (complete diets). These have a moisture content of around 10 per cent, normally contain preservatives and do not require refrigeration. They are hygienic, easy to store and available for cats of all ages.
It is impossible to compare the relative nutritional and monetary value of all available products. To find out if a commercial food is fully balanced, check the label. There should be some statement to this effect, such as ‘complete and balanced’, and some labels bear a distinguishing mark that denotes that they have been tested and approved. Some formulas contain textured vegetable protein (TVP) as well as animal protein, because TVP is cheaper.
You will probably base your choice on a product’s price, how readily your cat will eat it, and its labelled food content. The label usually lists the main food ingredients, and an analysis of certain nutrients such as protein, fat, and salt. Many manufacturers list the calorific value of the food, which can help you to decide how much to feed, and some indicate the amount that should be fed relative to body weight, stage of growth and activity level.
Canned commercial diets contain balanced nutrients but do not help maintain healthy teeth and gums. Feeding dry food as well helps to overcome this problem.
Foods from the veterinary clinic and pet stores
A number of international companies manufacture cat foods that are known as ‘professional formulae’.
Available only from selected pet stores and most veterinary clinics, these differ from supermarket pet foods in that their constituents are guaranteed. What this means is that a cat food made of chicken, for example, will always contain a specified amount of chicken, no matter how high the cost of poultry at the time of production. The products also do not contain the TVP that is found in some supermarket products.
Other foods sold only through veterinary clinics are therapeutic diets formulated to assist in the management of health problems, such as allergies, gastrointestinal disorders, kidney and bladder disorders, liver disease and obesity. Special diets are available for pregnant and lactating queens, to assist cats convalescing after surgery or trauma, or for those undergoing treatment for conditions such as anaemia or cancer.
If you want information about any of these diets, talk to your veterinarian.
Cats enjoy eating prepared liver, although it is unwise to feed it to cats more than once a week. Large amounts of liver can give the cat too much vitamin A, which causes skeletal problems.
If you want to prepare some or all of your cat’s meals yourself, and can ensure that it receives a properly balanced diet containing adequate amounts of animal protein, then by all means do so. If your cat has access to the outdoors, and to natural prey such as mice and lizards, then the chances are that the food it obtains outside will make up for any small deficiency in nutrients that might occur in your home-made diet. If it relies entirely on the food you provide, you must be absolutely sure that the diet you offer is properly balanced.
The animal protein for a home-cooked diet is usually derived from red meat, liver, kidney, heart, chicken, fish and (to a much lesser extent) milk. Remember that cooking food destroys some vitamins, and overcooking greatly reduces its nutritional value, so you need to supplement cooked food with the correct amounts and proportions of vitamins, just as reputable pet food manufacturers do.
Pet food supplements usually contain calcium carbonate or bonemeal (to create the crucial right balance of calcium and phosphorus), iodine, and vitamins A and D. You can purchase properly formulated supplements and various herbal preparations from a good pet store or some of the veterinary clinics.
Before basing your cat’s diet on home-cooked foods and/or using any form of supplement, though, talk to your vet. Excessive supplementation with vitamins and minerals can cause serious health problems.
Supplementation of a home-cooked or commercial diet may sometimes be necessary for certain health conditions, such as stress, illness or post-operative recovery. In such cases you should always ask your veterinarian for advice, and he or she may recommend a change to one of the specially formulated therapeutic diets.
Ingredients for home-cooked meals
Even if you decide to make commercial cat foods the basis of your cat’s diet, you may still find some of the information in this section useful.
Meat and meat by-products
All forms of red or white meat provide protein, B-group vitamins, fat and energy, but the relative amounts depend on the type of meat and also on the cut.
Protein (average %)
Fat (average %)
Energy (calories/100 g [3.5 oz])
Beef (medium fat)
Chicken is considered to be more digestible than red meat. All types of meat and offal are seriously deficient in calcium and slightly deficient in phosphorus, and the proportion of phosphorus to calcium is greatly excessive, ranging from about 10:1 for rabbit and ox heart to 30:1 for veal and 360:1 for fresh liver. Meat is also deficient in vitamins A and D and iodine, copper, iron, magnesium and sodium, and needs to be supplemented with the missing nutrients, particularly calcium, if it is to form a balanced diet. Meat is most nutritious if fed raw, because cooking destroys much of its vitamin B content.
Liver is a valuable food rich in protein, fat, fat-soluble vitamins (A, D and E) and the B vitamins. Cooking reduces the liver’s vitamin A content, but this is not a problem because too much vitamin A can lead to abnormal bone growth. As a general guide, do not let liver form more than 10 per cent of the diet.
There are two main types of fish. White fish has a nutrient composition similar to lean meat, contains less than two per cent fat, and is deficient in the fat-soluble vitamins (A, D, E and K).
Fatty and oily fish (such as tuna) contain high levels of vitamins A and D and high levels of unsaturated fatty acids, and feeding too much may cause a painful inflammation of fat deposits under the skin (steatitis).
Both white and oily types of fish contain high-quality protein and iodine, but are unfortunately deficient in calcium, phosphorus, copper, iron, magnesium and sodium.
Take care not to feed your cat too much raw (filleted) fish, as it contains thiaminase, an enzyme that destroys thiamine, one of the important B vitamins. Thiaminase is inactivated by heat, so it is best to cook fish before feeding.
Fish bones can cause problems if they get caught on a cat’s teeth or stuck in its throat, so if you are feeding whole (unfilleted) fish, make sure that the bones have been softened by pressure cooking (this rather old-fashioned style of cooking is the ideal way to prepare fish bones for both cats and dogs), boiling or stewing. Whole fish fed in this way is nutritionally better than meat.
Eggs contain iron, protein, most vitamins (except for vitamin C), fats and carbohydrates. Whole eggs contain about 13 per cent protein, 11.5 per cent fat, and provide about 160 kilocalories in every 100 g (3.5 oz). They are a well-balanced food and a useful source of animal protein and essential nutrients, particularly if fed raw. However, too much raw egg may be harmful, as egg white contains a substance called avidin that can reduce the availability of the B vitamin biotin, essential for many body processes including health of skin and hair, and proper muscle function. As a guide, feed no more than one raw egg per week to an adult cat. Cooking eggs by hard-boiling, poaching or frying reduces the avidin but also reduces their nutritional value, unfortunately. If you feed your cat the egg yolk only, you may increase the number of eggs to two or three per week. Remember that egg yolk on its own has a comparatively high fat content (about 31 per cent) and too much of this could cause obesity.
Milk, cheese and yoghurt
Dairy produce is high in protein, fat, carbohydrate, calcium, phosphorus, vitamin A and the B vitamins.
Whole milk is a useful source of calcium for kittens, and most cats like to drink it. You can serve it warmed, at room temperature or straight from the fridge – whichever way your cat prefers. Whole milk contains milk sugar (lactose), though, and as kittens mature their ability to digest this decreases. If fed more than small quantities of milk they may develop diarrhoea. Some adult cats are lactose intolerant, and if fed milk will develop an allergic, dry, itchy skin. For this reason low-lactose cat milk is manufactured and available in supermarkets.
Cream contains most of the milk fat and is a high source of energy, but if fed to excess it could result in obesity.
Cheese is a useful source of animal protein, and some cats like it. It does not contain lactose, so it can be fed in small chunks to cats that are known to have lactose intolerance. Pasteurized yoghurt also contains no lactose, but not all cats will consume it.
Fats and oils
A fat deficiency in the diet produces an itchy skin that may become dry and scurfy.
Fat is almost 100 per cent digestible and adds palatability to food – and, of course, cats love to eat it. Vegetable oils and fish fats are nutritionally better than animal fats. Safflower oil and corn oil are excellent sources of fatty acids – safflower is the best. If your cat’s diet is not already balanced, you can feed very small amounts of cod liver oil (about a quarter of a teaspoon three times a week). Be very careful with such supplementation, and before using it talk to your veterinarian. Cod liver oil contains excessive amounts of unsaturated fatty acids and these may cause steatitis.
Cats are spoilt for choice with so many brands of cat food available. Some will develop a favourite, although most cats enjoy a variety.
Most greens are rich in vitamin C, and vegetables are a good source of B-group vitamins. Cats can synthesize vitamin C in their body and don’t require a dietary source. Some cats will eat greens and vegetables if part of a stew with meat or fish – remember that overcooking reduces their nutritional value.
Grains provide carbohydrate and some proteins, minerals and vitamins. They are generally deficient in fat, essential fatty acids and the fat-soluble vitamins A, D and E.
Wheatgerm contains thiamine and vitamin E. Wheat, oats and barley have a higher protein content and less fat than maize and rice. Rice is palatable to cats and is used as an ingredient in a number of commercial cat foods.
Yeast is rich in the B vitamins and some minerals, and yeast preparations may be beneficial to older cats – they are safe even if used to excess. Despite anecdotal evidence, dietary supplementation with yeast does not prevent fleas.
Your cat’s normal diet should contain about five per cent fibre (measured on a dry basis), derived from vegetable matter. Fibre-rich diets (10–15 per cent) may be used to help reduce obesity, and can also be used as a dietary aid in diabetic cats, because fibre slows the absorption of glucose (the end-product of carbohydrate digestion) following a meal.
Bones and bonemeal contain 30 per cent calcium and 15 per cent phosphorus, magnesium and proteins. They are deficient in fat, essential fatty acids and vitamins. Too many bones can cause constipation, so ask your vet about quantities.
It is also useful to check with your vet before you feed chicken bones. Rather do not feed mature chicken bones unless they have been softened by pressure cooking, because they are liable to splinter. Fish bones can get stuck in a cat’s mouth or throat and should only be fed if they have been softened by cooking.
Make sure that clean, fresh water is always available. A cat’s normal daily requirement (from feeding and drinking) is about 40 ml (about 2.5 tablespoons) per kg (2.2 lb) of body weight. Water intake will vary according to the environmental temperature and your cat’s diet, increasing in proportion to the amount of dry food it consumes. It also increases if your cat is suffering from an ailment such as diarrhoea, diabetes or kidney disease.
Select a feeding area in a cool place where your cat can eat without interference, and use it routinely. Use bowls made of easily cleaned materials such as stainless steel, earthenware or plastic, and wash them after each use.
Cats are known as fussy eaters, but with good reason. A cat will eat only the freshest food it can find, turning up its nose at the smell of anything old or stale. This is because cats are stimulated to eat not only by hunger, but by scent, too. As a general rule, they prefer to eat their food warm or at room temperature because it has a better aroma. Some will eat cold, unused canned food that has been refrigerated immediately after use, but others will not.
Because canned (moist) cat food does not contain any preservatives, remove any that is uneaten within an hour or so. If you do not have fly screens fitted, and flies are a problem inside your house, remove the uneaten food immediately. Semi-moist food can be left in a bowl for several hours.
If your cat does not overeat, dry foods can be left out all day. If you wish to do this, purchase a proper self-feeder that keeps the food (and its aroma) enclosed and allows the cat free access.
Feeding your kitten
A queen’s milk is rich in protein and fat, and during the first few weeks after weaning, a kitten’s diet needs to reflect this. A growing kitten requires up to three times more energy intake per kg (2.2 lb) of body weight than does an adult, and because it has a limited stomach capacity it must be fed several times a day on a high-energy diet.
No matter how well fed, cats will succumb to instinctive behaviour and prey on birds and small mammals, should the opportunity arise.
There are many commercial brands of food specially formulated for kittens, both grain-based and meat-based, which you should consider rather than trying to formulate your own, homemade diet.
When a kitten is young you can also feed milk – although many vets do not recommend that you feed cow’s milk to either a kitten or a cat. If feeding cow’s milk appears to cause diarrhoea as your kitten gets older, it could be because of the milk’s lactose content, so change to a specially formulated cat milk.
As a general guide, a kitten aged 8–12 weeks should receive at least four meals a day of a commercial food or a home-cooked diet. You need to decide which you are going to use, and stick to it. Mixing home-cooked and commercial diets can lead to imbalances.
From three to six months feed at least three meals a day, and introduce the regime suggested below for adult cats.
Feeding your adult cat
Unlike dogs, which are competitive pack animals and will happily wolf down as much food as their stomach can handle, cats are solitary hunters and don’t usually eat a large amount at a time. Given the option they prefer to eat their daily ration in several small meals.
Most owners find it convenient to feed their cats a mixture of moist and dry foods. Dry foods can be left out for a cat to self-feed and moist foods can be fed in controlled amounts two or three times a day in the morning, early afternoon or early evening.
Late-night feeding can cause problems if your cat is confined to the house during the night, because most cats need to urinate and defecate within an hour or two of feeding.
If you are feeding more than one cat, you may need to feed them separately and some distance apart. This way a dominant cat cannot eat another’s food, and you can monitor their individual food intake.
How much to feed
Most cats tend to eat only enough to satisfy their energy needs. The amount of energy your cat uses will depend not only on its activity but also on its metabolic rate (the speed at which it burns up the energy). Every cat is an individual, and there can be as much as 20 per cent variation between two similar cats.
Your cat should be fed enough food to satisfy its energy needs, but no more – otherwise it will put on excess weight. Excess energy is stored as fat, deposited under the skin and under the abdomen (causing an appearance referred to as an ‘apron’). Some commercial diets are particularly palatable, and stimulate a cat to overeat. If you feed a commercial diet, ascertain its energy content from the label and feed your cat accordingly. If you feed a homemade diet, it may be more difficult to determine exactly how much to feed, and you will need to closely monitor your cat’s health.
The most important criteria for judging if you are feeding the correct quantity and balance are the health and appearance of your cat. If it is in good condition, alert and active with a healthy skin and coat, and maintaining its proper weight, it is almost certainly getting an adequate diet. If it has a scurfy skin, is shedding its coat excessively, is over- or underweight, appears dull or listless, is excessively hungry or often disinterested in food, you should talk to your vet.
Remember that if you give your cat treats between meals, these contain calories and you must make allowances for them in your cat’s overall diet.
These should not arise if you are feeding a properly formulated commercial diet. They may arise because a cat is:
ο receiving the wrong diet
ο eating, but a disease is reducing its ability to absorb or use food
ο not eating for a variety of reasons.
Underfeeding results in lack of energy, weight loss (the body burns up fat reserves, then the protein in the muscles) and finally starvation. It could also result in a deficiency of essential nutrients.
Overfeeding causes obesity and perhaps a toxicity caused by a nutrient excess (such as vitamin A).