Why is my old cat getting skinny but still eating

By Isabella Storyclaire

last updated September 16, 2024

Contributions sourced from

My Cat Is Getting Skinny but Is Still Eating

Many of us are aware of the risks in overfeeding our cats. Obesity in cats can seriously affect many aspects of their health and well-being. However, if a cat is too thin, similar health problems will occur. Not only is an undernourished cat ill-equipped to withstand threats to their health, it could be a symptom of an underlying disease. For these reasons it is important to give cats the right amount of food and ensure it is of adequate quality.

However, some of us may still observe that my cat is getting skinny but is still eating. AnimalWised explains the reasons why a cat is losing weight even though they should have the right levels of nutrition. We also show you what can be done about it.

Cats losing weight

When we have an overweight cat at home, we need to portion control their food and encourage exercise. While there are some medical conditions which can leads to a cat becoming obese, too much food, poor nutrition and a sedentary lifestyle are some of the biggest factors.

When a cat is losing weight, despite being provided with sufficient food, the problem is usually a little more complex. Two very important considerations to make are how much weight the cat is losing and how quickly it is happening.

Although rapid weight loss can be a problem in itself, more worrying is that it is the symptom of serious health problems in cats. If the cat is still eating normally, but losing weight regardless, the implication is that illness is preventing them from metabolizing their food properly. Physical conditions can present this problem, but it is important to note that psychological problems and changes in the environment may contributing factors.

The main causes of a cat losing weight while still eating are:

Hyperactivity
Psychological stress
Dietary changes
Hyperthyroidism
Gastrointestinal diseases
Diabetes
Parasites

In the below sections, we look into each cause of excessive weight loss in cats as well as what we can do about it. It is also important to know that how a cat eats can also affect their health and well-being. We explain more in our article about types of cat food bowls and feeders.

1. Hyperactivity

The amount of energy a cat will need throughout the day depends on various factors. Many of them are related to genetics. For example, some breeds are known to need to expend more energy (such as the Bengal cat), while are others are usually a little more sedentary (the Bombay cat).

Hyperactive cats will need more exercise and physical activity to release their excess energy. They will also likely have a high metabolism, meaning they quickly burn up the calories created by their food intake. The food we give a hyperactive cat will be burned up faster than the food we give a cat with a slower metabolism. We may have used correct guidelines on how much to feed a cat of a given size, but it is possible we have not figured in their hyperactivity.

When a cat gets skinny due to hyperactivity, we either need to increase their portion size or provide food which has different nutritional values. They will likely need a higher protein and lower carbohydrate diet, but you should check with your veterinarian regardless.

2. Psychological stress

Although we need to be considerate of physical problems leading to weight loss in cats, psychological issues may be a factor. When as cat is stressed, they may not eat out of anxiety. However, many cats suffering from stress may eat their food, but their nervous condition prevents them from being to hold it down. This is why we may see the cat vomiting, as well as other signs of stress.

If the cat has access to the outdoors, we may not be able to see the evidence of their vomiting. This would explain why the cat is losing weight, even though they appear to have a normal appetite.

The causes of stress in cats are myriad and we will need to look at the context of the individual. Cats are creatures of routine. Any change to this routine can be upsetting. Such changes include moving house, the arrival of a new baby in the home, adopting a new pet or changing your own schedule. Addressing these issues and providing the cat with more security will help reduce the effects of stress.

3. Dietary changes

Another important aspect of a cat's routine involves the food they eat. If we change the time we give them their food, it can lead to them not eating. However, the type of food is also vital. Some individual cats can be very fussy when it comes to the brand and type of food they eat. When we change cat food brands, it is possible they will eat less and lose weight accordingly.

Comparing wet food and dry food, we see that wet food has more protein and less carbohydrates than dry food. It also usually has more fat. If we start giving the cat only dry food, it is possible this is causing them to lose weight.

Many cat guardians want to give them the best diet possible and will opt for homemade food to do so. However, we need to ensure the nutritional levels are balanced for our cat's specific needs. It is possible giving our cat a homemade diet such as the BARF raw food diet causes them to lack certain nutrients and result in the cat becoming skinny.

4. Hyperthyroidism

Generally, when the reason your cat is skinny is due to a disease or health condition, other symptoms will also be seen. If the cat has cancer, for example, they may also start losing hair, developing growths and losing energy.

Also known as an overactive thyroid, hyperthyroidism may not have many other visible symptoms. In fact, the problem may be asymptomatic for a long period of time, even if there is internal damage being done. One of the earliest symptoms is that your cat will lose weight, even if they are eating normally.

Hyperthyroidism is when the thyroid overproduces the T3 and T4 hormones in the cats which results in the problematic symptoms. It can be treated with both drugs and surgery, but the earlier the diagnosis the better. This is why we should never ignore changes to the cat's well-being.

5. Gastrointestinal diseases

Since the gastrointestinal system is where the process of metabolizing food takes place, any diseases affecting the system can have knock-on effects. Such gastrointestinal diseases in cats include:

Colitis
Feline Enteric Coronavirus
Gastritis
Gastrointestinal obstruction
Inflammatory bowel disease (IBS)
Digestive cancers

If your cat is suffering from any of these problems, the resulted effects on metabolism can mean the cat eats food, but does not absorb the nutrients properly. This means the cat seems to eat normally, but becomes skinny over time.

A cat losing weight is only one symptom of gastrointestinal disease. Each disease will have specific causes and treatment, but some are very serious and potentially fatal. Take your cat to the veterinarian for an accurate diagnosis.

6. Diabetes mellitus

Unfortunately, diseases such as diabetes mellitus in cats are on the rise. Diabetes mellitus causes the body to be unable to produce sufficient insulin. As not enough insulin is produced, the cat cannot balance their glucose levels in the blood. There are various symptoms of diabetes in cats, although it is possible the cat will be asymptomatic in the early stages.

Apart from weight loss, cats with diabetes mellitus might have depression, vomiting, diarrhea, dehydration and even motor functions. If the cat does not have treatment, it can be fatal. If you suspect your cat has diabetes, take them to a veterinarian. They will likely change their diet to a low-carbohydrate option and will likely need daily insulin injections.

7. Parasites

There are various types of internal parasites which prey on cats. They can affect various parts of the body, but when they inhabit the gastrointestinal system, they can affect metabolism. For this reason, intestinal parasites in cats are a potential reason why your cat is skinny even though they still eat well. Type of feline parasite include:

Roundworm
Hookworm
Giardia
Physaloptera
Coccidia
Tapeworms

The parasites will often not only use up their resources, but they can prevent the intestinal tract from functioning properly. The result is often that the cat will start to lose weight.

Since intestinal parasites live in their body, discovering signs of an infestation can be difficult. This is why we need to look at other symptoms such as lethargy, vomiting, diarrhea and signs of egg remnants in their stool. Many of the reasons why a cat is losing weight have similar symptoms, which is why it is vital to go to the veterinarian. If they suspect parasites, they will test for which specific one and administer the appropriate antiparasitic medication.

Diagnosis and treatment of cat losing weight

When we detect that our cat loses weight, we must go to the vet to carry out the appropriate tests. You also need to be sure they are an incorrect weight, something we can see from the chart above. This shows you when a cat is overweight, underweight and the ideal weight by looking at their body shape. Please bear in mind, this may change a little according to the cat's breed.

After you take them to the veterinarian, it is important you also tell them any additional observations you have made regarding their recent health issues. They can use this information to best suspect a cause of weight loss and engage the appropriate tests.

These tests will most likely involve a blood test and perhaps a urine test to make the diagnosis. They can then rule out or confirm the presence of the aforementioned diseases. The veterinarian will then be able to provide the correct course of treatment and answer any additional questions you may have.

While your cat can lose weight even if they keep eating, they certainly will if they don't. Our video on why a kitten is not eating will explain more:

If you want to read similar articles to My Cat Is Getting Skinny but Is Still Eating, we recommend you visit our Diet problems category.

Why is My Cat Getting so Thin?

Weight loss is a common feline problem, particularly in senior kitties. Figuring out if your kitty is losing weight may be reliant on what you feel (rather than what you see). This is because a plush feline hair coat can readily mask how svelte or thin your cat is becoming. Note if your kitty feels bonier during grooming or petting and pay attention if your normally hefty feline friend is feeling light as a feather when you pick her up. Even if your cats appetite and behavior appear completely normal, unexplained weight loss should always be addressed with your veterinarian. The more common causes of feline weight loss are described below. Not enough foodWeight loss occurs when too few calories are being consumed. Some of the more common reasons cats will cut back on their food intake include:

A painful problem in the mouth such as a growth or dental disease.
Competition at the food bowl created by other cats or a sneaky dog.
Inability to get to the food bowl. For example, the kitty that can no longer jump up onto the food counter.
Disinterest in the type or brand of food being served. Finicky kitties will go for days, if not weeks, without eating a bite.
Stress or anxiety some cats quit eating in response to environmental stressors such as moving to a new household or the introduction of a new pet or human into their lives.

Gastrointestinal tract disease Gastrointestinal diseases can prevent normal digestion and/or absorption of nutrients, resulting in weight loss. Examples of the more common feline gastrointestinal ailments include:

While tapeworms are quite common in cats, rarely if ever are they a cause of weight loss. This is simply on old wives tale!Diabetes mellitusDiabetic cats often appear to be starving in the midst of plenty. In spite of a voracious appetite, they drop weight quite rapidly. This is because diabetes causes an inability to properly process and utilize the calories the kitty consumes.HyperthyroidismMany older kitties develop hyperthyroidism, a condition in which the thyroid glands produce an excess of thyroid hormone. While this disease can produce a variety of symptoms, what all hyperthyroid cats have in common is weight loss. This is because the excess thyroid hormone amps up the metabolic rate causing more calories to be burned.Organ failureWeight loss commonly occurs in response to dysfunction or failure of a vital internal organ such as the heart, liver, or kidneys. The weight loss is typically a result of a decreased appetite.TumorsCertain types of benign and malignant tumors are notorious for causing weight loss. This is because some cancer cells consume calories, virtually robbing the kitty of nutrition.

If you have any questions or concerns, you should always visit or call your veterinarian they are your best resource to ensure the health and well-being of your pets.