thumb|Dry cat food
Cat food is food specifically formulated for consumption by cats. In the 19th and early 20th centuries, cats in London were commonly fed horse meat sold by itinerant traders known as Cats' Meat Men or Women, who traveled fixed routes to serve households. The idea of specialized cat food developed later than dog food, as cats were long considered to be self-sufficient hunters. French writers in the 1800s criticized this view, arguing that well-fed cats were more effective hunters. By the late 19th century, commercial cat food emerged, with companies like Spratt's offering ready-made products to replace boiled horse meat. As obligate carnivores, cats require animal-based proteins for essential nutrients such as taurine and arginine, which they cannot synthesize from plant-based sources.
Modern cat food is available in various forms, including dry kibble, wet canned food, raw diets, and specialized formulations for different health conditions. Regulations, such as those set by the Association of American Feed Control Officials (AAFCO), ensure that commercially available foods meet specific nutritional standards. Specialized diets cater to cats with conditions like chronic kidney disease, obesity, and gastrointestinal disorders, adjusting protein, fat, and fiber levels accordingly. Weight control diets often include fiber to promote satiety, while high-energy diets are formulated for kittens, pregnant cats, and recovering felines.
Alternative diets, such as grain-free, vegetarian, and raw food, have gained popularity, though they remain controversial. Grain-free diets replace traditional carbohydrates with ingredients like potatoes and peas but do not necessarily have lower carbohydrate content. Vegan and vegetarian diets have limited studies demonstrating their safety. Raw feeding mimics a natural prey diet but carries risks of bacterial contamination and nutritional imbalances. The pet food industry also has environmental implications, as high meat consumption increases pressure on livestock farming and fish stocks.
Nutritionally, cats require proteins, essential fatty acids, vitamins, and minerals to maintain their health. Deficiencies in nutrients like taurine, vitamin A, or arginine can lead to severe health problems. The inclusion of probiotics, fiber, and antioxidants supports digestive health, while certain vitamins like E and C help counteract oxidative stress. The pet food industry continues to evolve, balancing nutrition, sustainability, and consumer preferences while addressing emerging health concerns related to commercial diets.
History
thumb|Engraving of a cats' meat man in an 1868 issue of Chatterbox, a children's magazine
During the 19th century and early 20th centuries, meat for cats and dogs in London, frequently horse meat, was sold from barrows (hand–carts) by traders known as Cats' Meat Men or Women. Henry Mayhew estimated in London Labour and the London Poor (1851) that the total number of cats in London might be 300,000. Each cats' meat seller had a particular route and served a few hundred households, their approach marked by mewing cats.
The idea of preparing specialized food for cats came later than dog food and dog biscuits. This was likely due to the idea that cats could readily fend for themselves. In 1837, a French writer critiqued this idea:
In 1844, another French writer, , expanded on this idea:
He goes on to say that it is all the more unreasonable to expect a cat to live from hunting in that cats take mice more for amusement than to eat: "A good cat takes many and eats few."
By 1876, Gordon Stables emphasized the need to give cats particular food:
In the same year, an advertisement for Spratt (better known for making dog food) said that their cat food entirely superseded "the unwholesome practice of feeding on boiled horse flesh". And, in another book on cats, Stables recommended the company's food:
Spratt, which began by making dog biscuits, was the first commercial producer of ready-made cat food.
Natural diet
thumb|Cat with prey rabbit
Cats are obligate carnivores—meaning, they are true carnivores and depend upon the nutrients present in animal flesh for their dietary needs in nature. Even domesticated cats can consume freshly killed meat from rodents, rabbits, amphibians, birds, reptiles and fish, whether through hunting or by having it provided by humans. The dietary needs of wild cats does not include any vegetable matter and consists solely of animal tissue. Whilst some plant matter is found in samples of the stomach content and faeces of cats the amount is negligible.
Cats cannot synthesize some nutrients that are non-essential for humans and required for survival, including the amino acids taurine and arginine. Some of these nutrients are not found in plants and must be sourced from meat in the natural diet. Cats lack the specific physiology to extract nutrients efficiently from raw plant-based materials, and require a high protein diet.
Packaging and labeling
In the United States, cat food using the label "complete and balanced" is required to meet standards that have been established by the Association of American Feed Control Officials (AAFCO) by either meeting a nutrient profile or passing a feeding trial. Cat Food Nutrient Profiles were established in 1992 and updated in 2014 by the AAFCO's Feline Nutrition Expert Subcommittee. The updated profiles replaced the previous recommendations set by the National Research Council (NRC). Certain manufacturers label their products with terms such as premium, ultra premium, natural and holistic. Such terms currently have no legal definitions. However, "While most of the food supplied comes from within the US, the FDA ensures that standards are met within our borders even when components come from countries with less stringent levels of safety or label integrity."
Gastrointestinal health
The gastrointestinal tract (GIT) is the source of nutrient absorption, making it integral to overall health.
Cats with gastrointestinal diseases must consume an easily digestible diet with the appropriate nutrients provided by easily digestible ingredients and in the correct ratio which is recommended to be fed in small portions frequently throughout the day, so as not to overwhelm the digestive system.
Commercial foods
Most store-bought cat food comes in either dry form, also known in the US as kibble, or wet form (canned or in pouches). Some manufacturers sell frozen raw diets and premix products to cater to owners who feed raw.
Dry
left|thumb|Dry (extruded) cat food example
Dry food (8–10% moisture) is generally made by extrusion cooking under high heat and pressure. Approximately 95% of dry pet foods are extruded. During this process, the meat is first ground up, cooked under very high heat, and processed so it becomes a powder. The powder is fed into a massive mixer. In the mixer, additional supplements are added; then it's cooked again at very high heat to turn it into a dough, which is molded in the shape of kibble, and baked. At this point, it no longer smells like meat. Fat may be sprayed on the food afterwards to increase palatability, as well as other minor ingredients, such as heat-sensitive vitamins, which would be destroyed in the extrusion process. Dry food is most often packed in multi-wall paper bags, sometimes with a plastic film layer; similar bag styles with film laminates or coextrusions are also used.
Dry foods contain high amounts of carbohydrates in order to maintain their shape and structure. Concerns have been raised that there is some association between the carbohydrate content and risk of obesity and type 2 diabetes in felines.
Wet
right|thumb|Wet (canned) cat food example (Fish flakes in jelly)
thumb|Various kinds of canned cat food
In much of Europe, the UK and the US, canned or wet food (75–78% moisture) generally comes in aluminum or steel cans in sizes. It is also sold in foil pouch form.
Treats
A variety of cat treats are commercially available. These can be divided into dry cat treats, wet cat treats, and semi-moist treats. A 2004 survey in the US and Australia found 26% of cats received treats on a daily basis.
Soy isoflavones
Soy is often used in commercial cat food diets as a vegetable protein. In one study more than half of commercial cat foods surveyed contained soy isoflavones. Genistein and daidzein, both of which occur in soybeans, inhibit the enzymes thyroid peroxidase and thyroxine 5-deiodinase. This causes decreased thyroxine and triiodothyronine concentrations. In response to decreased triiodothyronine levels the body will produce more thyroid-stimulating hormone (TSH) to normalize triiodothyronine levels. In soy-fed cats this has been shown to result in increased thyroxine levels.
Specialist diets
Cat food may be formulated for a variety of specialist diets, for therapeutic or other purposes. A 2004 survey in the US and Australia found 3.6% of cats were fed therapeutic diets.
Renal diet
A renal diet is formulated for cats that are living with chronic kidney disease (CKD). This is a highly prevalent condition in the feline population and is most common in aging and older cats. It has been shown that the lifespan of cats experiencing CKD can be extended by as much as 2 years when receiving therapeutic diets rather than regular maintenance diets. Although the diet of a healthy cat should be high in protein, at times it is medically necessary for a cat to eat a low protein diet. For cats living with chronic renal disease, low protein diets lower the amount of nitrogenous waste in the body, helping to decrease the strain put on the kidneys. Cats with this condition should be fed a diet with high quality protein sources that have adequate amounts of the amino acids taurine and arginine.
Low protein diets have been linked to health defects such as lack of growth, decreased food intake, muscle atrophy, hypoalbuminemia, skin alterations, and more. Cats on lower protein diets are more likely to lose weight, and to lose lean body mass. With a decreased glucose tolerance, clinical observations have confirmed that cats consuming large proportions of metabolizable energy, in the form of carbohydrates rather than protein, are more likely to develop hyperglycemia, hyperinsulinemia, insulin resistance, and obesity.
Formulating these diets with higher amounts of fat is important to make sure the food is palatable in the absence of protein and promote an increased caloric intake. Omega-3 fatty acids are included in therapeutic diets because of their anti-inflammatory properties to aid the diseased kidneys.
High energy
A high energy diet is generally high in fat. Compared to carbohydrates and protein, fat provides much more energy, at 8.5 kcal/g. High energy diets generally have a fat content greater than 20% on a dry matter basis. A high energy diet is appropriate for cats who are undergoing growth, recovering from illness, are pregnant or lactating, as their energy requirements are higher than otherwise. A lactating or gestating cat requires a nutrient-dense and highly digestible diet to withstand the high levels of stress being placed on her body. These conditions are found in cat food that is formulated for growth, performance, or high energy during all life stages. Studies that relate the number of meals offered to cats per day to their daily activity levels have shown conflicting results. It has been shown that cats offered four meals a day or a random number of meals a day have similar energy levels, greater than those fed only one meal per day. It has been postulated that this increased energy level could be due to purported spikes in activity before being fed, known as food anticipatory activity. The age, sex, and whether cats are intact or have been spayed/neutered are all factors controlling activity level.
As cats age, there is evidence that their metabolic energy requirements may increase, but other evidence suggests that metabolic energy needs are not dissimilar at different ages. Furthermore, it has been shown that cats over 12 years old are more likely to be underweight than younger cats, so a high calorie diet may be appropriate to treat weight loss, and thus to maintain an appropriate body condition score. while pregnant; during lactation it is recommended that the cat consumes 240–354 kcal ME per kg of body weight. A recovering cat needs enough energy (calories), as well as more protein and fats. Critical care diets are formulated to be highly palatable and digestible, as well as high energy density. Studies have shown that cats fed lower energy diets had a significantly reduced incidence of obesity, as the typical indoor pet cat does not need more energy than their resting energy requirement. For an average cat weighing 10–11 pounds (about 5 kg), it would have a resting energy requirement of 180–200 kcal/day.
Along with energy input and output, specific nutrients can be important in weight control diets. Fiber is an important component that helps control weight, along with various other benefits. A source of soluble and fermentable fiber helps to increase the movement of digesta through the gut and decrease gastric emptying. This helps to increase satiety in cats, potentially decreasing feeding rates and voluntary energy consumption. Fermentable fiber promotes healthy mucosa and commensal bacterial growth and improved digestion/nutrient absorption. Prebiotic fibers like fructooligosaccharides (FOS) and mannooligosaccharides (MOS) decrease the number of pathogenic bacteria and increase the number of beneficial bacteria in the gut. They also help to maintain microbial balance and a healthy immune system. Fiber is fermented in the colon to produce short-chain fatty acids which can be used as an energy source. Fermentable fiber has been demonstrated to enhance general health and decrease inflammation. At the same time, these studies still show similar results that prove their effects of controlling fatty acid metabolism for weight control, to avoid the need for weight loss diets.
Unconventional diets
Raw food
Raw feeding is providing uncooked ingredients to cats. Most of the diet will consist of animal-based ingredients, though fruits, vegetables and supplements are often added.
Commercial raw diets can undergo High Pressure Pasteurization (HPP), a process which kills bacteria and pathogens, including salmonella, using high water pressure. This technique is USDA approved and allows raw food to remain uncooked while greatly improving its safety and shelf-life. The researchers at Tufts University analyzed the nutritional information and contents of 77 different dry cat food diets. 42 of these diets contained grain, while 35 were labeled as grain free. The major ingredients and amounts were determined for each diet and then analyses were conducted comparing the two groups. It was found that the grain free diets had a lower mean carbohydrate content than the diets containing grain; however, there was a very wide range and lots of overlap between the two groups in both their carbohydrate contents. Some grain free diets even had a higher amount of carbohydrates than the diets containing grain. Calorie amounts were similar for both diets.
Vegetarian and vegan
Vegetarian, vegan, or plant-based cat food has been available for many years. It excludes any meat and animal derivatives, using plant and synthetic ingredients instead. The most common reason for owners to feed their cat a plant-based diet is the ethical impact on farm animals and animal rights. Other reasons are cat food's environmental impact and a distrust of the healthiness of conventional cat food. There has been controversy over feeding cats a vegetarian or vegan diet.
alt=A black cat with white paws eating plant-based wet cat food from a small bowl.|thumb|A cat eating wet plant-based cat food.
A number of veterinary and animal welfare organizations do not recommend or recommend against feeding cats a plant-based diet. American Society for the Prevention of Cruelty to Animals recommends against plant-based diets for cats, because cats are not adapted to it. Similarly, the World Small Animal Veterinary Association states that cats should not be fed a vegetarian or vegan diet. The British Veterinary Association does not recommend plant-based cat food, stating that suitable synthetic alternatives are lacking for some essential fatty acids and amino acids.
Some organizations that advocate vegan or vegetarian diets for people also advocate for plant-based cat food. The International Vegetarian Union says feeding cats plant-based food is desirable, as it avoids contributing to the meat industry, and PETA supports it for the same reason. The Vegan Society has approved a number of vegan cat foods and treats with its Vegan Trademark.
Health impact on cats
Relatively little research on plant-based diets for cats is available, with studies being either small, or subject to selection bias to get to large numbers of plant-based cats. A 2023 systematic review found that although there was no significant evidence of adverse effects the quality of the studies were poor and high-quality studies are lacking. The authors recommended a cautious approach to feeding a vegetarian diet for cats and dogs and suggested that commercial diets are better than home-made. Improvements in coat condition and weight control are other reported benefits. Additional monitoring, especially in the beginning, and working with a vet is recommended by the author of the study when changing a cat's diet, including when changing to a plant-based one.
Urinary acidity is a candidate for such monitoring. It is important for cats' health that the acidity of their urine is in the right range. If the urine isn't very acidic, struvite crystals can form, which is dangerous. Plant-based proteins tend to be less acidifying than animal-based proteins, which means that cats on a plant-based diet may be at a higher risk of having too little acidity in their urine. Acidifying supplementation is available to correct this when needed, it cannot be used preemptively, because too much acidity is also problematic.
Concerns
A 2020 study evaluated vegan pet foods including one for cats in the Brazilian market and found it had nutritional inadequacies when compared to AAFCO recommendations. It was found to be lacking in arachidonic acid, an essential fatty acid for cats, and low in potassium. Compared to the FEDIAF standards, it was additionally found to be low in arginine, calcium, Ca/P ratio, and too high in copper and zinc. Another study, looking at 8 vegan pet foods labelled as suitable for cats, found none met all the guidelines. It adds that these problems have been found in commercially prepared meat-based foods too.
Another concern is that synthetic taurine comes in different forms that are absorbed in different degrees. This is said make taurine supplementation to plant-based cat food "extremely difficult" in a BBC Science Focus article.
Supplementation
Cats, as obligate carnivores, require certain nutrients (including arginine, taurine, arachidonic acid, vitamin A, vitamin B12 and niacin) from their food, they cannot create these themselves. Plant sources may lack these or not provide them in sufficient amounts, and supplementation or fortification is an important part of vegan cat food.
Due to the complex process and supplementation to ensure a nutritionally adequate diet, plant-based cat food cannot reliably be home-made. For example, when 25 online recipes for home-made plant-based cat food were analysed, none met the recommended amounts for all nutrients and all were deficient in iron.
Homemade
Many pet owners feed cats homemade diets. These diets generally consist of some form of cooked or raw meat, bone, vegetables, and supplements, such as taurine and multivitamins. Homemade diets either follow a recipe, such as the BARF (bone and raw food) diet which provides a series of options for the pet owner to make, or rely on the constant rotation of ingredients to meet nutrient requirements.
Another 2019 study on a range of homemade diet recipes found online and in books has also found nutritional inadequacies. The authors mention that vegetarianism and support for organics food are common reasons for trying such a diet, but does not specifically address the adequacy of vegetarian or organic diets.
Nutrients and supplements
Vitamin deficiencies can lead to wide-ranging clinical abnormalities that reflect the diversity of their metabolic roles. Twelve minerals are known to be essential nutrients for cats. Calcium and phosphorus are crucial to strong bones and teeth. Cats need other minerals, such as magnesium, potassium, and sodium, for nerve impulse transmission, muscle contraction, and cell signaling. Many minerals only present in minute amounts in the body, including selenium, copper, and molybdenum, act as helpers in a wide variety of enzymatic reactions.
Many nutrients can cause a variety of deficiency symptoms in cats, and the skin is a vital organ that is susceptible to dietary changes in minerals, protein, fatty acids, and vitamins A and B. Cats show dietary inadequacies in their skin through excess or inadequate oil production, and skin toughening. This results in dandruff, redness, hair loss, greasy skin, and reduced hair growth.
Macronutrients
The macronutrients – proteins, fats, and carbohydrates – provide energy to the cat. Proteins are also broken down into essential amino acids and fats into essential fatty acids.
The natural feral cat diet has a metabolizable energy (%ME) breakdown of 52% crude protein, 46% crude fat, and 2% nitrogen-free extract (roughly corresponding to carbohydrates). This is calculated from the dry-matter values of 62.7% crude protein, 22.8% ethereal extract (crude fat), and 2.8% NFE. Citrulline would typically go on to the kidneys to make arginine, but because cats have a deficiency in the enzymes that make it, citrulline is not produced in adequate quantities to make arginine. Arginine is essential in the urea cycle in order to convert the toxic component ammonia into urea that can then be excreted in the urine. Because of its essential role, deficiency in arginine results in a buildup of toxic ammonia and leads to hyperammonemia. The symptoms of hyperammonemia include lethargy, vomiting, ataxia, and hyperesthesia, and can be serious enough to induce death and coma in a matter of days if a cat is being fed an arginine-free diet. These symptoms appear quickly because diets devoid in arginine will typically still contain all of the other amino acids, which will continue to be catabolized by the body, producing mass amounts of ammonia that very quickly build up with no way of being excreted.
Essential fatty acids
A fatty acid molecule consists of a (COOH) group attached to an aliphatic chain. There are many types of fatty acid with different such chains. These different types have somewhat different properties. Saturated fatty acids have no carbon=carbon double bonds, while polyunsaturated fatty acids have more than one such bond in each molecule. The main form of fatty acids in diet is fats or triglycerides, which consist of three fatty acid groups attached to a glycerin molecule.
Fatty acids can become attached to different molecules such as carbohydrates or proteins, and can implement a wide range of functions in the body. Alpha-linolenic acid is an omega-3 fatty acid that aids in the maintenance of the skin's water barrier. Arachidonic acid is also essential to cats because they are unable to create it from linoleic acid due to an absence of the Delta 6 desaturase enzyme.
Dietary fibers are plant carbohydrates which cannot be digested by mammalian enzymes. They increase motility by stimulating rhythmic contractions of the distal portion of the small intestine, which potentially decreases fermentation in the small intestine while increasing it in the large intestine for further fatty acid absorption. The microorganisms present in the colon are responsible for the fermentation of the fiber into short-chain fatty acids and for the production of some vitamins.
Prebiotics
Prebiotics are short-chain carbohydrates classified as fibers with an added aspect as they selectively promote the growth of beneficial bacteria. When zinc is supplemented in diets, skin scaliness decreases. A deficiency in dietary copper is also related to collagen abnormalities, hypopigmentation of the skin, and alopecia. Sources for cats include liver and supplements in the forms of copper sulphate and cupric oxide.
Selenium
Selenium works with vitamin E as antioxidants to remove the free radicals that are damaging to the body and the skin. Dietary sources of selenium are naturally occurring in selenomethionine and tuna. In addition to its many other functions, vitamin A plays an important role in the keratinization of the skin, hair and nails along with assisting in the development of various epithelial tissues throughout the body. Common ingredients which help to incorporate the proper levels of vitamin A into feline diets include various types of liver as well as fish oils. Supplements of Vitamin C reduce oxidative DNA damage in cats prone to kidney injury, and can be beneficial to add into diets for cats with renal diseases. Vitamin C is not essential for cats and it is not required by the Association of American Feed Control Officials (AAFCO); however, it is commonly added into pet foods as an antioxidant.
Unlike humans, felines are able to synthesize Vitamin C in the liver via the glucuronate pathway, as they lack glucokinase activity. The simple sugars glucose and galactose are used as input. This pathway naturally maintains ascorbic acid (active Vitamin C) at an adequate level; therefore it does not need to be separately included in their diet.
Unlike dogs and humans, cats metabolize vitamin D2 and vitamin D3 slightly differently. A dose of Vitamin D2 is approximately 70% as effective as the same amount of vitamin D3.
Vitamin E
Vitamin E as an antioxidant in gastrointestinal health cat food diets can have a positive effect of improving the animal's immune function and prevent against infections. Vitamin E is a free radical scavenger that functions as a chain-breaking antioxidant to prevent free radical damage of cell membranes. Vitamin E aids in protecting cells from highly reactive oxygen species within the lungs, muscles, skin, brain, tissues and red blood cells. Supplementation of vitamin E in the diet benefits the immune system and improves resistance to infections and diseases. They are included in the diet to increase the number of bacteria and microbes that are normally present in a healthy gut. Examples include prevention of allergies, diarrhea, symptoms relating to stress, etc. Free radicals amplify inflammation by causing release of pro-inflammatory cytokines. Free radicals can be caused by many factors such as stress, disease and age. Combinations of antioxidants have been reported to improve serum vitamin status, suppress lipid peroxidation and distributes the effects of exercise on the immune system. The most common antioxidants found in cat gastrointestinal diets are vitamin E and vitamin C.
Taurine
Cats have a sulfinoalanine decarboxylase deficiency, preventing the synthesis of taurine from cysteine. Being able to create their own only in small amounts, dietary taurine is essential for cats. Taurine deficiency in cats will develop into dilated cardiomyopathy, heart failure, blindness, deafness, and reproductive issues. In the 1980's these symptoms were prevalent and linked to a lack of taurine. Commercial cat food was then successfully supplemented with taurine, and this practice continues to this day. Synthetic taurine is typically used for supplementation and found to be effective.
Food allergy
Food allergy is a non-seasonal disease with skin and/or gastrointestinal disorders. The main complaint is excessive scratching (pruritus) which is usually resistant to treatment by steroidal anti-inflammatory drugs. The exact prevalence of food allergy in cats remains unknown. In 20 to 30% of the cases, cats have concurrent allergic diseases (atopy/flea-allergic dermatitis). A reliable diagnosis can only be made with dietary elimination-challenge trials. Allergy testing is necessary for the identification of the causative food component(s). Therapy consists of avoiding the offending food component(s).
Recalls and contaminants
The broad pet food recalls starting in March 2007 came in response to reports of renal failure in pets consuming mostly wet pet foods made with wheat gluten from a single Chinese company beginning in February 2007. Overall, several major companies recalled more than 100 brands of pet foods with most of the recalled product coming from Menu Foods. The most likely cause according to the FDA is the presence of melamine in the wheat gluten of the affected foods. Melamine is known to falsely inflate the protein content rating of substances in laboratory tests. The economic impact on the pet food market was extensive, with Menu Foods alone losing roughly $30 million from the recall. Some companies were not affected and utilized the situation to generate sales for alternative pet foods.
Bisphenol A
A 2004 study reported that food packaged in cans coated with bisphenol A is correlated with the development of hyperthyroidism in cats.
Environmental impact
The greenhouse gas emissions of animal agriculture are significant, and in the US, 25-30% of those are estimated to come from pet food. While a single cat is smaller than a human, they do eat more animal products on average, offsetting some of their lower food emissions from size and contributing a significant amount to the emissions of a household. Most of the emissions from cats come from the food they eat.
In a study on the impacts of the pet food industry on world fish and seafood supplies, researchers estimate that 2.48 million metric tonnes of fish are used by the cat food industry each year. It was suggested that there needs to be "a more objective and pragmatic approach to the use of a limited and decreasing biological resource, for human benefit." Marine conservation activist Paul Watson argues that the reduction in forage fish such as those commonly used in cat food (sardines, herring, anchovy etc.) negatively affects fish higher up the food chain like cod, tuna and swordfish, not to mention marine mammals and birds.
A study for 2020 in the US found that while a significant portion of cat food is made of animal agriculture by-products, 49.2% of the animal products in conventional cat food are human-consumable. The study also found that if all the world's cats were to eat a plant-based diet, 900 million fewer farmed land animals would be slaughtered each year. Tanya Stephens argues that because vegetarian pet-food is heavily processed and needs to be supplemented with nutrients it is not as sustainable as proponents claim. The increase in popularity of human-grade and byproduct-free pet food means there is increasing pressure on the overall meat supply.
In 2015, there were an estimated 77.8 million dogs and 85.6 million cats in the USA. The consumer desire to feed their pets premium foods which advertise healthy and human-grade ingredients, coupled with more pet ownership, requires more meat; this could require more land for raising livestock. In a study conducted by Okin in 2017, he suggests that if a quarter of all animal protein used in the food of American pets was human-grade, it would be equivalent to the energy needs of 5 million Americans. This trend has led to a higher need for animal protein, which may have a detrimental effect on sustainability.
Lowering protein levels in feline diets may help to improve the sustainability of both the human and pet food system by decreasing pressure on livestock agriculture and ultimately improving environmental effects. Other ways to improve sustainability include using animal byproducts (organs not eaten by humans), plant (mainly pea) proteins, and insect proteins. In addition, feeding less food to an animal helps reduce the carbon footprint and chances of obesity.