Cat Losing Weight And Drinking A Lot Of Water – Causes

Pet owners are familiar with the daily task of filling their cat’s water bowl. They are also aware of the look and feel of their fur baby.

A cat’s water consumption and weight can vary depending on its diet, the weather, and age. If you’ve been keeping a close eye on your cat’s health, you will be able to notice the slightest changes.

Cat Losing Weight And Drinking A Lot Of Water

If your cat is drinking more water, there could be an underlying medical condition that is undiagnosed and untreated. When this is paired with a noticeable weight loss, your cat’s health might be at risk.

Extreme Weather Conditions

Most cat owners take note of their cats’ regular water consumption and weight during different seasons. On hotter days, you may notice that your cat will drink excessively but may not eat as much.

If this persists for a few days, your cat will begin to appear thinner. Find ways to keep your cat cool in extremely hot weather.

You can wrap a towel around a frozen water bottle and keep it nearby your cat. Or let your cat stay in an airconditioned room.

But suppose you’ve started to notice excessive drinking and weight loss in your cat without any substantial change in their diet or environment.

In that case, it can be a sign of a medical or behavioral condition.

Anxiety Or Stress In Cats

Contrary to popular belief, animals like cats and dogs can also experience negative emotions like stress and anxiety.

It can be caused due to unfamiliar surroundings, a change in their routine, or other unidentified factors.

Excess stress and anxiety can also cause behavioral and eating problems in your cat, leading to excessive drinking or weight loss.

Suppose you notice your cat drinking more water or losing weight in a specific environment or circumstance.

In that case, the chances are that this behavior is caused by anxiety and stress rather than a medical condition.

Gastrointestinal Problems

GI tract-related issues could affect a cat’s weight. You will first notice a loss in appetite. Internally, GI tract issues hinder proper digestion.

Your cat will have difficulty absorbing nutrients, which will lead to weight loss.

In cats, some well-recognized GI problems include pancreatitis, intestinal parasites, inflammatory bowel disease, and other pancreatic issues.

Common symptoms of GI issues are loss of appetite, weight loss, vomiting, diarrhea, and lethargy. It also causes dehydration which may be why your cat drinks a lot of water during this time.

Treatment at the vet for GI parasites could be as simple as a deworming procedure. For other GI issues, your vet may recommend medication and supportive care.

Diabetes Mellitus

Cats can suffer from diabetes just like humans. Diabetes is a disease caused by a hormonal imbalance in the body.

The cat’s body makes a hormone called insulin, which helps digest the sugar in the blood. This dissolved blood sugar provides energy to the cells of the cat’s body.

If a cat is suffering from diabetes, there can be problems with insulin production in its body. It leads to several health disturbances such as lack of energy, excessive thirst, urination, and weight loss.

The diagnosis for the type of diabetes in your cat can only be performed at the vet through blood tests.

Kidney Disease

Excessive thirst, urination, and weight loss can be caused in cats due to kidney diseases or infections. The kidneys are a paired organ responsible for filtering excretion from the blood.

The kidneys also maintain the body’s water balance, making sure that the cells remain hydrated. If your cat suffers from kidney disease, it may have trouble retaining water in its body, leading to excessive drinking.

Kidney disease can also be caused by an infection, or a UTI, making your cat FEEL like they need to urinate more often. It leads them to make more frequent trips to the cat box.

Why Is My Cat Losing Weight And Drinking A Lot Of Water

Kidney disease can present many different symptoms, such as loss of appetite, vomiting, diarrhea, and nausea. It will lead to your cat losing weight.

The vet can diagnose kidney disease through blood tests, and it can be treated with medication.


The thyroid glands are a pair of small organs in the body located in the neck of your cat. These glands make several different hormones that aid the metabolic functions of the body.

This includes digestion, uptake of energy, and regulation of several bodily processes.

Excessive thirst and weight loss can be caused by a condition of the thyroid glands called hyperthyroidism.

Hyperthyroidism occurs when the glands’ cells multiply faster than usual, resulting in excessive growth. It leads to overproduction of the thyroid gland hormones, which upsets the metabolic balance of the cat’s body.

If your cat suffers from hyperthyroidism, it may drink more water. It will also experience weight loss due to digestive problems, loss of appetite, and frequent bouts of vomiting or nausea.

Hyperthyroidism is also diagnosed through a blood test, and a chemical called iodine is used to treat this condition.

Old Age

You may notice your cat losing weight as it grows older.

According to vets, well-known reasons for weight loss in senior cats include dental problems, exocrine pancreatic insufficiency, hyperthyroidism, chronic renal disease, diabetes mellitus, and inflammatory bowel disease (IBD).

Excessive thirst and urination can result from old age as well. An older cat is more likely to drink more often and thus urinate excessively.

If you have an elderly cat, regular visits to the vet can ensure that they remain healthy and free from diseases as much as possible.

Visiting The Vet

The best way to diagnose and treat excessive drinking and weight loss in your cat is to visit the vet.

The vet will usually order a complete blood panel to ensure all essential hormones and blood cells are within the normal range.

If the vet detects abnormalities in the blood tests, they might prescribe additional tests, like an ultrasound to check the kidneys.

Once the vet has established a diagnosis, they will prescribe the necessary treatments for your cat.

The medical conditions mentioned above also provide the most common treatment applicable.

If your vet does not find any underlying medical concern, they may diagnose it as a behavior disorder.

It will require other types of intervention like training or addressing the source of anxiety or stress with your cat.


There are several possible reasons for weight loss and excessive drinking in cats. A diagnosis by a certified veterinary doctor is essential to identify and address this problem.

The reasons for developing some of the conditions mentioned above are usually not apparent as several factors can cause them.

Genetics, diet, breed, and the environment can all have a significant impact on your cat’s health and quality of life.

Keeping your cat healthy requires paying attention to their eating, excretion, and sleeping habits, along with their normal behavior throughout the day.

If you notice anything odd or out of the ordinary that continues for a significant amount of time, it is best to consult a vet to rule out any underlying health conditions.