I can see that my cat’s hunger decreases. This is a status called anorexia. It is dangerous for cats because they are easy to catch fatty liver or fatty liver syndrome. This is a life-threatening condition. It can grow when the liver must handle an enormous amount of fat stored to supply energy for cats’ bodies. 

Weight loss can affect cats. When finding that my cat is thin gradually, I researched to know the answer to the question, “why is my cat losing so much weight?

Reasons why your cat loses weight

There are many reasons and elements causing weight loss at cats. Owners need to observe and recognize to meet veterinarians for examination and advice. 

Worry, stress or depression

Stress takes place not only humans but also animals, especially cats. Cats stressful mentality can make them lose their weight, and this affects their eating. Cases that can make cats sad include excessive noise, other animals in the feeding area, or dirty dishes. Additionally, if you have nourished cats recently, they can feel you and your house strange or under threat by other old animals of you (fierce dogs, cats, etc.). Some cats that consider only one person as their owner. They will be resolute to quit eating even the whole week when their owner leaves. This leads to weight loss and affects their health.  

Although people do not consider stress as a big reason causing the phenomena of weight loss, prolonged stress can affect cats.


Although it is not that all cats lose their weight because of this disease, cancer is a quite popular culprit. Other symptoms that often appear include anorexia, being apathetic, and hiding.

Intestinal cancer (lymph and leukocyte tumor) is one of the reasons causing weight loss at cats. Though this disease often occurs at old dogs more than at cats, it is still a dangerous disease. The tumor appears in the stomach, intestinal or rectal tract, and cats will have symptoms such as vomiting, anorexia, or stomach ache. Moreover, cancers of gastrointestinal, liver, gallbladder, and kidney can also cause weight loss at cats.


This may be because of hormonal insulin production or the reactivity with it. This often creates the weight loss status at cats, and they usually have a change in hunger. Cats catching diabetes can also drink much water, urinate much more than usual, act slowly, develop urinary tract infection, and have smelly breath. 

Feline infectious peritonitis (FIP)

Cats catching FIP often seem to be weak and usually have a fever without reaction with antibiotics. 

Stomach or intestine diseases

Many different statuses at the gastrointestinal can lead to weight loss for cats. In this case, other symptoms may consist of anorexia and vomiting. The everyday affairs about digestion causing weight loss at cats consist of inflammatory bowel disease, food allergy, or some infections.   

Parasitic disease

Kittens catching diseases of hookworm and roundworms, prolonged tapeworm disease, or toxoplasmosis can lose their weight.

Although cases of weight loss related to parasites are not as famous as before since owners often give deworming for their cats each month now, the important thing they need to know is that not all kinds of drugs have the same effects and can prevent all types of worms. The inrush of parasites is often because cats eat and drink outdoor indiscriminately.

Intestinal parasites

Also known as worms, intestinal parasites can be the reason for unintentional weight loss at cats. Though symptoms are not always present, these parasites can also cause diarrhea, flatulence, vomiting, and breathing problems.


A lot of old cats show their weight losses. It is difficult to determine the exact reason for this affair. Diseases such as diabetes and kidney disease become more popular when cats are old.   


Your cat can have a tasty feeling. Cats can eat much more than usual, but they still lose their weight. Hyperthyroidism is the result of a tumor producing benign hormone on thyroid, making thyroid hormone concentration increase.

Hyperthyroidism can lead to weight loss and the increase in drinking, urination, action, vomiting, diarrhea, and muscle wasting. In stages later, it can even lead to heart problems or death. Old cats can be easy to develop this disease, too.


If your cats stop eating suddenly and have a signal of weight loss but still be healthy, they can have sore teeth, which can lead to the problem. Salivation is also another signal of a tooth problem.

Toothache can be one of the reasons for weight loss in cats because cats will be difficult to chew food particles when they have swollen gums. Treatment for this problem will help to improve anorexia as well as regain health balance for them.

Dehydration, electrolyte disorder

The reason is that cats catch viral infectious diseases: Coronavirus, Panleukopenia, FIV, causing immunodeficiency syndrome as HIV/AIDS at humans. 

Prolonged diarrhea because of digestive disorder, overeating high-protein and fatty food, food allergy are reasons causing weight loss at cats, too. 

Hepatic and renal impairment

This is because of infectious diseases, liver fluke disease, intoxication from the environment, chronic urological disease, diabetes, and anemia. 

Old cat disease

Cats more than seven years old will be slow. They can catch asthenia heart failure, respiratory, tumor or cancer illness, etc. Thin and weak cats, as well as the ones losing their weight, should have a veterinary examination. 

Kidney disease

Unlike other diseases’ symptoms, when cats catch kidney disease, they will not lose weight immediately. When you find that they begin to be sick gradually, they have had disease incubation for a quite long. To cats catching kidney disease, they will drink much water and urinate many times.

Heart disease

Similar to kidney disease, cats catching heart disease will not lose their weight immediately.

Food change

In some circumstances, maybe weight loss is not because of diseases. It may be because of food change, making cats feel boring and quit eating. Additionally, the amount of new food may not ensure enough nutrition as well as calories for cats.

If you are planning to change food for your lovely cats, you should consider nutritional ingredients carefully, as this is a significant element determining their health and weight. Moreover, food change for cats needs to take place gradually from 3 to 5 days before letting them use the new type of food altogether. Just ensure that the change process does not affect too much to the supply of enough amount of food and nutrition for your cats!

Treatment and taking care of cats losing weight at home

If weight loss is in control with the guidance of the veterinarian, this will be beneficial to fat cats. However, if weight loss occurs super quickly or not in your desire, it can be a symptom of some severe problems related to health.  

To determine the reason causing weight loss at cats and have the best treatment plan for owners as well as pets, bosses should meet veterinarian to do a complete physical examination, blood test and urine analysis for cats. 

The veterinarian can advise you to treat your cats’ symptoms, especially if they are dangerous. Nevertheless, this cannot replace treatment for reasons causing the status of weight loss.

Depended on the reason for cats’ weight losses, there is a series of regulations about treatment solutions and diet change to vet. Even old cats can receive weight-loss treatment.  

Once veterinarian assigns appropriate treatment solutions, please be sure that you will supply a balanced diet, use vitamins and minerals for your cats when the veterinarian recommends. You even must force your cats to eat or implement nutrition infusion through a vein. Sometimes you can use stimulants for hunger to make cats eat again.

Examination and observation in the right way are a super essential step, especially if your cats’ status does not improve fast. Supervision is necessary for this stage, too. You should implement recommendations in the treatment of the veterinarian. And if your cats do not satisfy the treatment solutions, contact the veterinarian immediately! 

Weight loss because of some certain statuses of the gastrointestinal can be vetted by implementing appropriate diet changes at cats. If your cats catch inflammatory bowel disease or other affairs making food absorption difficult, you should prepare a digestible diet for them. You should use drugs stimulating the appetite for your cats, too.

Why Is My Cat Losing Weight?


A lot of cat owners worry about their cats’ weight loss. Cats lose their weight because of many elements. If the weight loss is too quick or out of control, it can be the symptom of several serious affairs related to health. If your cats are having the phenomena of weight loss, you need to understand the reasons leading to weight loss above to have timely remedies. Depending on different reasons, you will have appropriate treatment solutions and diet change for them.


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