Weight Loss In Cats With Normal Blood Work – Causes and What to Do

Weight Loss In Cats With Normal Blood Work - Causes and What to Do

As fur parents, we tend to worry a lot if our cat’s weight suddenly changes for no clear reason, and even more, concerning is if the tests come back normal. We may even start to doubt the accuracy of the tests that were performed. If the weight loss is drastic despite no change in our cat’s appetite, we cannot help but fear the possibility of cancer or other life-threatening conditions.

If you are worried or frustrated by your cat’s significant weight loss with normal blood work, you are by no means alone. Like you, other cat parents also seek answers regarding their pets’ unexplained weight loss. Hopefully, this article will shed some light on your cat’s weight loss problem and what you can do to help your furry pal recover.

Why is my cat losing weight but still eating?

If you notice your feline friend losing weight despite eating the same or more than usual, it is likely caused by an underlying medical condition. Serious health problems like cancer, hyperthyroidism, irritable bowel syndrome, and parasite infections can all affect your cat’s metabolism and appetite. That means your pet might eat the same amount of food, or even more, but still lose weight.

If you notice any strange symptoms along with your cat’s weight loss, do not hesitate to give your vet a call. Unintentional weight loss can be indicative of a life-threatening illness, so it is best to have your furry friend screened right away. 

Causes of weight loss in cats with normal blood work

Not all feline weight loss is caused by something serious. Sometimes, the culprit might be a behavioral issue that just requires a few tweaks to your cat’s diet or environment. However, if the weight loss issue comes with other unusual symptoms, then your cat could have a health problem.

Below are some of the common causes of sudden weight loss in cats:

1. Changed eating habits

Cats might refuse to eat due to boredom, and this can cause a bit of weight loss. Like people, they prefer some variety in their diet to keep them interested. This is actually not surprising because, like their wild ancestors, they are born to hunt different types of prey. In the wild, cats would hunt for birds, frogs, insects, mice, and many others, depending on which is available. Since Fluffy is now an indoor cat, a lack of diversity in her diet might eventually lead to food boredom.

Another reason your cat may limit her food intake might have to do with seasonal changes. She might intentionally avoid eating so much during summer and then suddenly increase her intake during the colder months. That is because cats spend most of their time sleeping when the weather is hot, so they do not need to burn a lot of calories. However, in the winter, they need more energy to keep themselves warm and maintain their body temperature.

If your cat changed her eating habits due to food boredom or weather changes, it should not cause you concern. However, if Fluffy eats more than usual but is losing some weight, you need to have her checked by the vet as soon as possible.

2. Old age

As cats become older, their metabolism slows down and their activities become less. Hence, they might not eat as much as when they were younger. You will notice that their nutritional needs as well as their food portion sizes change. Some will also become picky eaters over time, and weight loss will result. 

3. Stress or depression

Have you recently moved to a new residence or brought home a new pet or baby? Then this might be the cause of Fluffy’s lack of appetite.

Cats do not deal well with changes. As territorial animals, they rely on routine and predictability, as this is how they survive in the wild. If something changes in their environment, they can become stressed, and this can cause them to become withdrawn and less interested in food.

Knowing how sensitive our whiskered friends are, it is therefore crucial to help them acclimatize to any changes. That includes introducing them gradually to a new pet, baby, or home. Also make sure that they have their own safe space, away from the noise and other people or pets, to keep them calm and comfortable.

4. Pregnancy

Your cat’s body goes through a lot of changes during pregnancy. A future mother cat can experience so much stress that she might refuse to eat, especially if she is going to deliver her babies soon. Her nutritional needs and food preferences might also change, so you will need to be more patient and loving with her. 

Even if your pregnant cat loses her appetite, make sure to provide her with enough food and water that is easy to access. Once she is done giving birth to her kittens, she will lose a significant amount of weight and start eating more than usual. This sudden increase in appetite will help sustain her milk production and keep her well-nourished while she cares for her kittens.

5. Intestinal parasites

Your cat’s unintentional weight loss might also be caused by intestinal parasites like hookworms, roundworms, tapeworms, heartworms, flukes, or many others. Aside from weight loss, you may also notice symptoms like diarrhea, black and tarry stools, vomiting, and malnutrition. If you notice these symptoms, make an appointment with your vet so that the issue can be addressed right away.

6. Dental problems

If your cat is struggling with dental disease, she might have difficulty eating and swallowing her food. Dental problems can be very painful, and might also cause her to drool or drop her food. Because of tooth decay and gum inflammation, it will be difficult for her to chew food properly, which might be the reason she seems to eat less or completely refuses to eat. 

7. Other medical conditions 

If your cat’s drastic weight loss is accompanied by other strange symptoms, it is usually indicative of a bigger health problem. Unintentional weight loss can be caused by several underlying health problems, including:

  • Hyperthyroidism
  • Inflammatory bowel disease
  • Food allergies
  • Chronic kidney disease
  • Diabetes
  • Cancer
  • Pancreatitis
  • Heart disease
  • Feline viral disease
  • Arthritis

These conditions can be very serious, so if you spot any strange symptoms along with your cat’s weight loss, it is best to see your vet immediately. Since it can be hard to pinpoint the culprit behind your cat’s drastic weight loss, your vet might require several tests to make an accurate diagnosis. 

Depending on the severity of your cat’s symptoms, tests might include blood testing, stool testing, urinalysis, radiographs, endoscopy and biopsy, and dental check-ups. Going through such tests can be stressful and frustrating for you and your pet, but these procedures are necessary so that your vet can determine exactly what is wrong with your cat. 

How much weight loss in a cat is concerning?

If the weight loss is intentional, your cat should not lose more than one percent of her body weight per week. You can also talk with your vet about how much weight loss is normal and acceptable. 

If the drastic weight loss has something to do with an underlying medical condition, then you and your vet need to agree on a treatment plan to address the issue. Any unintentional weight loss accompanied by other unusual symptoms can be concerning, as it could be linked to serious conditions ranging from parasitic infections to cancer. 

Additionally, if your cat loses weight too quickly, she might develop hepatic lipidosis, or fatty liver disease. This happens when the cat’s body breaks down fat too quickly, causing an accumulation of fats in the liver. Without immediate treatment, this disease can cause liver failure and death.

What does normal blood work mean?

When unexplained weight loss is accompanied by normal blood work, it can be frightening as well as frustrating. Most cat owners would fear that something is wrong despite the normal results, which is understandable.

Blood work can tell you a lot about your cat’s overall health, and while the tests might come back normal, it does not always mean your cat is healthy. Vets do need to perform a combination of tests before finally confirming the health of your pet. Some of these tests are:

  • Urinalysis to check for conditions such as liver and kidney disorders, and diabetes
  • Cytology for cancer screening
  • A thyroid test to determine your cat’s thyroid hormone levels
  • Stool test to check for parasites
  • CBC, or complete blood count, to check if your cat’s blood condition is normal
  • Blood serum chemistry test to detect problems with the liver and kidneys

Keep in mind that your vet will need to know your cat’s medical history and symptoms. He will also perform a physical test on your cat and, if something shows up, those problems will be treated first before working on your cat’s weight-loss issue.

Helping your cat regain weight

Managing your cat’s weight loss problem might involve a comprehensive treatment plan as well as appropriate feeding and environmental enrichment, depending on what has caused the issue. Your vet might recommend the following:

  • Feed your cat a balanced diet that includes a high amount of protein, enough healthy fats, some carbohydrates, and lots of vitamins and minerals.
  • Make sure your cat always has access to clean drinking water to keep her hydrated. If your cat hates drinking water from her bowl, you can invest in a cat water fountain to entice her to drink more.
  • Choosing healthy food alternatives if your cat is struggling with allergies or inflammatory bowel disease.
  • Warm the food to encourage your kitty to eat. Simply place your cat’s food in the microwave for a few seconds to make the food more appealing.
  • Administer an appetite stimulant like Nutri-Cal to increase your cat’s appetite and boost her calorie intake. 
  • Giving your cat constant access to dry food. Cats naturally prefer eating small meals several times a day, and even more so when they are pregnant.


Your cat’s sudden weight loss can be caused by several issues, which may be behavioral or medical. If you notice your cat is suddenly lighter when you cuddle her, it is advisable to start monitoring her eating habits. Is her appetite the same? Do you notice any other symptoms? 

If you suspect that your cat is ill, make an appointment with your vet immediately. Once you have figured out what is wrong with her, it will be easier to address the issue and, hopefully, return your cat to a healthy weight as soon as possible.

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