Why Won’t My Cat Gain Weight? (Causes & Solutions)

why won't my cat gain weight

Have you ever looked at your feline friend and wondered, “Why won’t my cat gain weight?” It’s a common concern among cat owners, and it’s crucial to understand that maintaining a healthy weight is as important for our cats as it is for us.

Just like in humans, being underweight can lead to health issues in cats. But don’t worry, we’re here to help you understand and solve this problem.

Why is My Cat Not Gaining Weight?

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There could be a myriad of reasons why your cat isn’t gaining weight. It could be as simple as not eating enough, or it could be something more complex, like a medical condition.

Cats, like humans, can suffer from diseases that can cause weight loss, such as hyperthyroidism or kidney disease. It’s also possible that your cat is eating enough but not absorbing the nutrients effectively, which could be due to issues like inflammatory bowel disease (IBD).

It could be as simple as not eating enough, which could be due to a variety of reasons. To understand why a cat might not be eating, you can read our article on How Long Can A Cat Go Without Eating.

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Signs Your Cat is Underweight

So, how can you tell if your cat is underweight? Here are some signs to look out for:

  • Physical signs: An underweight cat may have visible ribs, spine, and hip bones. You might also notice a loss of muscle mass, making them appear less robust than they should be.
  • Behavioral changes: Cats that are underweight might show changes in their behavior. They could be eating more than usual but still not gaining weight, or they might be less active and playful.

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Remember, these signs can also be symptoms of other health issues, so it’s always a good idea to consult with a vet if you notice any changes in your cat’s weight or behavior.

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Common Causes of Weight Loss in Cats

Medical Conditions

Let’s dive into the medical side of things. There are several health conditions that could be the sneaky culprits behind your cat’s inability to gain weight.

  • Hyperthyroidism: This is a condition where the thyroid gland produces too much thyroid hormone. It’s like having the engine running at full speed all the time, causing your cat to burn calories at a faster rate.
  • Inflammatory Bowel Disease (IBD): Just like in humans, cats can suffer from IBD. This condition can make it difficult for your cat to absorb nutrients from food, leading to weight loss despite a good appetite.
  • Pancreatitis: This is an inflammation of the pancreas that can interfere with digestion. If your cat’s pancreas isn’t working properly, they might not be getting enough nutrients from their food.
  • Liver and Kidney Diseases: These vital organs have many functions, including detoxification and waste removal. If they’re not working correctly, it can affect your cat’s overall health and weight.
  • Tumors: Certain types of tumors, especially those related to the digestive system, can cause weight loss in cats. One such condition could be Mouth Cancer In Cats.


Moving on from medical conditions, let’s talk about some unwelcome guests that might be living in your cat’s body – parasites.

Parasites like worms can take up residence in your cat’s intestines and feed on the nutrients from the food your cat eats.

This means that even if your cat is eating enough, they might not be getting all the nutrients they need to maintain a healthy weight.

Dietary Issues

Finally, let’s not forget the role of diet in weight gain.

Just like us, cats need a balanced diet to stay healthy. If your cat’s diet is lacking in essential nutrients, or if they’re not eating enough, they won’t gain weight.

Common dietary mistakes include feeding your cat a diet that’s too low in protein or fat, or relying too heavily on dry food, which can be less nutritious than wet food.

A balanced diet is the cornerstone of good health for your cat. If you’re looking for more variety in your cat’s diet, check out our articles on various food options for cats, such as Can Cats Eat Applesauce, Can Cats Eat Lobster?, and Can Cats Eat Banana Bread.

Remember, every cat is unique, and what works for one might not work for another. It’s always a good idea to consult with a vet or a pet nutritionist to determine the best diet for your cat.

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Helping Your Cat Gain Weight

Dietary Changes

cat dieting and cat nutrition. fat cat and measuring tape. weight control concept

So, we’ve talked about the potential reasons why your cat might be underweight. Now, let’s discuss solutions, starting with dietary changes.

A balanced diet is the cornerstone of good health for your cat. If your cat is underweight, you might need to adjust their diet to include more high-protein and high-fat foods. These nutrients are essential for weight gain and overall health.

You might be wondering, “Should I feed my cat wet food or dry food?” Well, both have their pros and cons. Dry food is convenient and can be left out for your cat to graze on throughout the day.

However, wet food is usually higher in protein and can be more appealing to picky eaters. You might need to experiment a bit to find what works best for your cat.

Treating Underlying Medical Conditions

the veterinarian weighs an overweight pet on a scale, fat cat

Next up, let’s talk about the importance of veterinary care. If your cat is underweight due to a medical condition, treating that condition is crucial for helping your cat gain weight.

The treatment will depend on the specific condition. For example, hyperthyroidism might be treated with medication, surgery, or radioactive iodine therapy.

On the other hand, inflammatory bowel disease might be managed with dietary changes and medication.

In some severe cases, such as Seizures, you might need to consider difficult decisions. It’s always best to consult with a vet for a proper diagnosis and treatment plan.

Preventing Parasites

Last but not least, let’s discuss parasites. Regular deworming is essential for preventing parasites that can cause weight loss in cats.

Your vet can recommend a suitable deworming schedule based on your cat’s lifestyle and risk factors.

Other preventive measures might include keeping your cat indoors to reduce their exposure to parasites and maintaining a clean living environment.

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Now, let’s answer some frequently asked questions about cat weight issues.

How can I help my cat gain weight?

You can help your cat gain weight by providing a high-protein, high-fat diet, treating any underlying medical conditions, and preventing parasites. It’s also important to provide plenty of fresh water and encourage regular exercise to maintain overall health.

Is my cat too skinny if I can feel her spine?

If you can easily feel your cat’s spine, ribs, or hip bones, your cat might be underweight. However, some breeds are naturally slim, so it’s best to consult with a vet if you’re concerned about your cat’s weight.

Why is my cat so skinny and not eating?

If your cat is skinny and not eating, it could be due to a medical condition, stress, or dietary issues. In some cases, it could be due to serious health issues, such as Feline Leukemia. It’s important to consult with a vet to determine the cause and find a solution.

Why is my cat so skinny I can feel her bones?

If you can easily feel your cat’s bones, your cat might be underweight. This could be due to a variety of reasons, including medical conditions, parasites, or dietary issues. It’s best to consult with a vet if you’re concerned about your cat’s weight.

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