Everyone’s appetite fluctuates somewhat from day to day. However, if your cat goes 24 hours without eating, there may be a serious health condition. Hyporexia is a condition in which one is eating noticeably less food, while anorexia is a condition in which one stops eating anything at all. Each condition indicates the presence of an emotional or physical disorder.

Anorexia is very serious in cats, and requires immediate attention. Within as little as a day the dangerous process of catabolism, or the breaking down of one’s own muscle mass for nutrients, can begin.

Anorexia is not a disease in itself, and can indicate many different causes. The main reason is stress, though a cat’s total refusal to eat can also be caused by learned food aversions and physical discomfort. A cat will never simply decide not to eat.

Anorexia is most commonly a reaction to stress caused by environmental changes, such as hospitalization or boarding. A hospitalized cat's pre-existing illness may be complicated by the cat refusing to eat. When under veterinary care, cats can be stressed by lack of privacy, intrusive noise and bright lights, and changes in food and routines. Losing a feline companion can also stress a cat to the point of refusing to eat, as can introducing a new cat into the living situation.

Learned Food Aversions 

A learned food aversion occurs when a cat learns to dislike a food, thus avoiding it. When an ill cat is fed a therapeutic diet, it may develop an aversion to the food, associating it with the illness. Force-feeding any food can also lead a cat to avoid the forced food. 

Cats may also refuse food when they are experiencing some kind of physical discomfort. The discomfort can come from pain, nausea, or reaction to a drug administered to the cat for another condition. Dental disease is an especially common source of pain that will dissuade a cat from eating.

Anorexia is a serious condition, and needs to be treated quickly.  If your cat has refused to eat for one full day, it should have a full veterinary examination, followed immediately by treatment, which is aimed at getting the cat to eat.

While a vet’s guidance is necessary, many forms of treatment can be administered at home by the cat’s owner. Force feeding is the easiest, and requires no special equipment. The owner simply holds the cat’s mouth open with one hand, while placing small bite-sized balls of protein-rich soft food into the cat’s mouth, then holding the cat’s mouth shut until it swallows the food. This must be repeated until the cat’s entire meal is consumed. However, this process is not usually enjoyable for cat or owner, and might lead the cat to develop an aversion to the forced food. Alternately, food can be forced into the cat’s mouth with a syringe. 

However, the veterinarian will want to investigate the potential cause of the appetite loss before asking you to try force feeding at home. An examination in the clinic may reveal a dental issue that is preventing your cat from eating due to pain. A cleaning and extraction of infected teeth will be done, providing your cat with the relief needed to allow eating again.

If your pet is on a medication that is causing your pet to lose appetite, the veterinarian will try a new medication. If your pet is dehydrated and experiencing nausea, vomiting or diarrhea due to the lack of food intake, intravenous therapy may be offered in order to stabilize your cat’s health before the replacement medication is administered.

There are also several appetite-stimulating medications that can be given to anorexic cats, such as mirtazapine, which stimulates the cat’s appetite and reduces nausea. Mirtazapine is used by humans as an antidepressant.

Whether the cat is treated by force feeding, tube feeding, medication, or some combination thereof, calories should be given gradually in small meals. If too many calories are given at once to an anorexic cat, the cat could develop problems with vomiting or diarrhea.

To prevent your cat losing appetite, it’s important to create a low-stress environment, provide a healthy and appealing diet, and monitor your cat for signs of digestive trouble.

Keep your cat’s environment peaceful and quiet, with easy access to privacy, and make sure the cat has a calm area in which to eat—away from the litter box. It’s important that your cat can get to its food easily. If it is wearing an E-collar to keep it from irritating a wound, remove the E-collar for meal times. If your cat is a social eater, it may help to pet or brush the cat before meals. 

Your cat’s diet should be consistent and appealing, with fresh high quality food that is to the cat’s taste. Some cats will only eat dry food, while others prefer canned food. Older cats, who have a weaker sense of smell, may be enticed to eat if canned food is slightly warmed, as this gives it a stronger odor. 

Be vigilant about watching your cat for any irregularities in eating. If your cat refuses its food or vomits, it may be suffering from nausea, which must be treated immediately. Nauseous cats can be more likely to eat cold or room temperature food, as cooler foods have weaker odors.

The treatment cost of your cat’s loss of appetite will depend on the cause. Anorexia treatments can cost from $500-$4000, averaging $800. Treatment of dental abscess averages $900. However, if your cat has lost its appetite because of stress, there may be no treatment cost beyond a veterinary examination.