Hepatic Lipidosis In Cats: How Long Can A Cat Go Without Eating?

While a fat cat might appear to be a happy cat, there is actually a deadly condition that your cat can develop from being obese. Cats are highly dependent on protein in their diet, the protein is needed for fat metabolism which is then used for energy. "Feline Fatty liver" can develop when cats go for days without food (can be as little as 36 hours). 

Hepatic Lipidosis in cats (feline fatty liver) is when the liver stops functioning properly and stores fat, instead of metabolizing it. The cells swell and become "fatty". This build up of fat inside the liver cells can be associated with diseases that cause decreased appetite, or metabolic disorders such as diabetes or in some case there is no identifiable cause. 

It is important to seek veterinary help as soon as possible for the best prognosis.  Your veterinarian will use ultrasound and  blood tests (to evaluate liver enzyme levels) to help make a diagnosis. Once a diagnosis is made it will be critical to find the underlying cause of why your cat was not eating as this will help determine the best course of treatment.  

Why Are Cats At Risk For Hepatic Lipidosis?

This unique combination of cats' physiology, dietary requirements, and metabolic adaptations makes hepatic lipidosis a significant concern for cat owners and veterinarians. Prompt recognition and treatment are essential for a successful outcome in affected cats.

Obligate Carnivores: Cats are obligate carnivores, meaning they have a biological requirement for meat in their diet. Their livers are adapted to metabolize high amounts of protein and fat. However, if a cat suddenly stops eating, their liver can become overwhelmed with fat, leading to hepatic lipidosis.

Rapid Mobilization of Fat: When cats stop eating, their bodies quickly start breaking down fat stores to meet energy needs. Unlike other animals, cats have a limited ability to convert fat into glucose, which is essential for energy. As a result, excessive fat mobilization overwhelms the liver, leading to the accumulation of fat within liver cells.

Metabolic Adaptations: Cats' livers are not as efficient as those of other animals in handling large amounts of fat. Their metabolic pathways are adapted to deal with the high protein content of their natural diet. Sudden changes, such as fasting or a drastic shift to a high-carbohydrate diet, can disrupt these metabolic processes and lead to hepatic lipidosis.

Risk Factors: Cats are prone to stress-induced anorexia, which can trigger hepatic lipidosis. Additionally, obese cats or those with certain medical conditions are at higher risk. Female cats, especially those who have recently given birth, are also more susceptible.

Hepatic lipidosis can progress rapidly in cats, leading to severe liver dysfunction and even death if not treated promptly. The condition requires intensive veterinary care, including nutritional support and sometimes hospitalization.  Diet changes and supplements like liver support, probiotics and enzymes can also help.  Natural treatments for hepatic lipidosis can be lifechanging for cats. 

Author:   Susan Blake Davis

Revised and Updated:  3/20/2024

Originally Published 9/1/2019

Hepatic Lipidosis "fatty liver" in cats

Dr. Dr Gordon: My cat is very sick. I took him to the vet because he had become very lethargic. After the vet ran some tests, he determined that my cat has “fatty liver” disease. My cat is very overweight to begin with, but I did not know that he could get this disease just by being “fat”. The vet said that treatment can be very difficult. Can you help me understand this disease? RK

Lypozyme

Lypozyme is recommended by veterinarians to help cats with hepatic lipidosis. Lypozyme optimizes fat digestion and metabolism. 

Dear RK: I am very sorry to hear that your cat is not feeling well. From time to time, veterinarians encounter cats that develop fatty liver disease or hepatic lipidosis. This is a disease that is specific to the cat, since its’ dietary requirements and metabolism are much different than the dog’s metabolism. Let me explain.

If a cat, especially an overweight cat, stops eating, it can suffer serious liver problems. Cats are extremely dependent upon having protein in their diets. Unlike many species, cats cannot adequately synthesize their own protein from other building blocks. If a cat is not taking in enough protein, it will start breaking down proteins from its body, including important muscle and liver proteins. At the same time, the body is starving for energy, so it mobilizes fat stores for calories, and carries this fat to the liver for processing. Normally, the liver would metabolize these fats to use them for energy, store them, or secrete them through bile. If the liver is missing some of the proteins needed for fat metabolism, all a liver cell can do is store the fat. The fat builds up inside the cells, a condition called hepatic lipidosis, or "fatty liver,"and the cells swell, pinching off bile ducts. Bile, with all its waste products, cannot empty from the liver into the intestine as it normally does, and the cat becomes jaundiced.These changes in the liver occur within 36 hours of not eating. Since the liver cannot metabolize the fat for energy, the cat suffers further starvation, setting up a vicious cycle of fat mobilization and liver damage. Although this buildup of fat inside liver cells is often associated with diseases that cause decreased appetite, or metabolic disorders such as diabetes, we also see cases that are idiopathic, or have no identifiable underlying cause.

The diagnosis is made by doing blood tests that may first indicate an increase in the liver enzyme values. Usually an ultrasound exam of the abdomen should be the next step, which usually shows the liver that is extremely “shiny” on the ultrasound image. A fine needle aspirate can then be sent to the lab so that the pathologist can definitively diagnose the problem.

Treatment of the condition can be difficult. If there are any underlying diseases that are causing the cat to have stopped eating (infection, inflammation, etc.), these must be addressed to allow the cat to feel better. But the cornerstone of therapy is to get the cat to eat once again. Many times, this is more difficult than it sounds, for the cats in this situation usually do not feel well enough to have any appetite  and they need a lot of calories to offset the metabolic effects of the disease. To counteract this, the veterinarian will usually suggest syringe feeding a very high protein and high carbohydrate diet up to 4 times a day. Sometimes appetite stimulants are used to encourage eating. If the patient is resistant to syringe feedings, a special feeding tube may need to be surgically placed in order to provide the cat with adequate nutrients to reverse the process. Once the cat starts eating on its own, the feeding tube can be removed.

Fortunately, most cases of fatty liver are reversible with intense veterinary care. Although most cats present being very ill and lethargic, the majority are able to recover as long as they begin eating on their own. This may take several days of hospitalization at the veterinary clinic however. This underlies the importance of keeping cats at a healthy weight and realizing that any change in the cat’s normal routine or food, can cause the cat to stop eating, possibly resulting in “fatty liver”.

In addition to getting the cat on a healthy diet, supportive care using liver supplements can help. Products such as Pet Liver Rescue, Special SAMe and digestive enzymes containing lipase such as Lypozyme may be helpful in addition to the care provided by your veterinarian.