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The Shrinking Kitty Syndrome — Why Your Aging Cat Is Losing Weight

Dropping ounces or pounds is a common occurrence with older kitties, and there are a number of reasons why it happens. Five diseases that can cause weight loss in aging cats and 6 suggestions for enticing kitty to eat and stay well-nourished.

older cat weight


  • Weight loss in older cats is common, however, it’s important to have your kitty seen by your veterinarian if she seems to be shrinking in size
  • Sometimes a senior kitty’s drop in weight is due to stressors in his environment
  • There are also a number of disorders that affect older cats than can cause weight loss, including diseases of the heart, respiratory and endocrine systems, the gastrointestinal tract and the kidneys

Editor's Note: This article is a reprint. It was originally published November 08, 2016.

Weight loss in older cats is fairly common, which may be why many owners of aging kitties don’t realize dropping weight is very often an indication of an underlying disease process. And this is true even if your cat’s appetite and food consumption hasn’t changed.

Keep in mind the loss of just 1 pound in a 10-pound cat means she’s lost 10 percent of her total body weight, which is excessive. If your senior kitty seems to be shrinking, it’s very important to make an appointment with your veterinarian before she gets any thinner or starts showing signs of illness.

Stress Can Cause Weight Loss in Cats

There are many potential causes of weight loss in older cats, both pathological and non-pathological.

Non-pathological triggers typically involve stressors in kitty’s environment. Perhaps you’ve recently added a dog to the family who’s presenting a real or perceived threat to your cat. Or maybe your work schedule has changed and necessitated an adjustment to your cat’s mealtimes.

Another environmental stressor that can affect a kitty’s eating habits and weight is competition at mealtime. This occurs when all the cats or pets in the household are fed in close proximity to one another. Cats tend to feel much more comfortable when they are able to eat their meals in private.

Essentially any change, no matter how minor in your cat’s daily routine or environment is a potential stressor, so it’s a good idea to give some thought to what might be creating anxiety for a senior kitty who is losing weight.

5 Diseases That Cause Weight Loss in Older Cats

Just as with all animals, including humans, diseases that produce weight loss are more common in older cats than younger ones. These include acquired heart disease, respiratory disease, endocrine disorders, gastrointestinal (GI) disease and kidney disease.

  1. Heart disease — Adult onset heart disease in cats is the result of damage to the heart structure that occurs over time. The most common type of acquired heart disease in kitties is cardiomyopathy, which accounts for about two-thirds of feline heart conditions.

    Cardiomyopathy is a structural abnormality in the muscle surrounding one or both chambers of the heart, with the result that the left ventricle (and once in awhile, the right ventricle as well) becomes thickened, dilated or scarred.

    The abnormality also interferes with the heart’s ability to collect and pump blood, which can lead to congestive heart failure and fluid in or around the lungs. Other complications of cardiomyopathy include blood clots that cause paralysis, and sudden death.

    It is thought that both genetics and lifestyle (weight, diet and physical activity) play a role in the development of feline cardiomyopathy. Occasionally, the condition develops secondarily to another disorder such as anemia, hyperthyroidism or high blood pressure.

    Three types of heart disease account for almost all the primary cardiomyopathies diagnosed in cats: hypertrophic cardiomyopathy, restrictive cardiomyopathy and dilated cardiomyopathy.
  2. Respiratory disease — An upper respiratory tract infection or chronic sinusitis can interfere with your cat’s sense of smell, which can decrease his interest in food, ultimately resulting in weight loss.

    Chronic feline asthma can cause weight loss, especially as a kitty gets up in years. Abnormal tissue growth or primary tumors of the lung can also result in weight loss, along with lethargy and difficulty breathing.
  3. Endocrine disease — Two of the most common endocrine disorders affecting older cats are hyperthyroidism and diabetes. Feline hyperthyroidism has increased dramatically in the U.S. in the last 30+ years.

    It's the most common endocrine disorder of kitties, with over 10 percent of cats over the age of 10 diagnosed with the disease.

    About half of cats that develop hyperthyroidism have an increased appetite; however, about 90 percent of those kitties ultimately lose weight because a side effect of too much circulating thyroid hormone is an increase in metabolism.

    Other symptoms include high blood pressure, frequent vomiting, increased body temperature, heart and respiration rates and hyperactivity.

    A combination of increased appetite, weight loss and sudden, unexpected bursts of energy in an older cat is a definite sign you might have a kitty with hyperthyroidism.

    Diabetes is the result of not enough insulin being released from the pancreas, or an abnormal release of insulin coupled with an inadequate response of the body’s cells to the insulin.

    Sugar in the bloodstream cannot get into the cells of the body, so the body starts breaking down fat and protein stores to use as energy. As a result, no matter how much a diabetic cat eats, she loses weight.
  4. GI disease — There are many types of gastrointestinal disease that can cause weight loss, but one of the most common in cats aged 10 and older is GI lymphoma, which is an incurable form of cancer. Kitties with the disease are often lethargic and have a poor appetite that triggers a drop in weight.

    Inflammatory bowel disease (IBD) has been linked to GI lymphoma in cats. Feline IBD is a collection of GI disorders that ultimately causes an increase in the number of inflammatory cells in the lining of the digestive tract. Food sensitivities and allergies play a role in IBD and contribute to compromised immune function.

    Chronic diarrhea and/or vomiting are typical symptoms, resulting in inflammation and scar tissue in the lining of the intestine. These changes can then evolve to cancerous cells and progress to lymphoma of the GI tract.
  5. Kidney disease — It’s estimated over half of cats 10 years and older suffer from chronic kidney disease (CKD), which means the kidneys have been gradually and irreversibly deteriorating over a period of months or years. Symptoms of failing kidneys include increased thirst and urination, leaking urine (especially at night), vomiting, diarrhea, lack of appetite, weight loss, depression, anemia and overall body weakness.

    As you can see, there are a number of ways your cat’s body can start to break down as he gets up in years, resulting in weight loss and a host of other problems. This is why it’s so important to proactively manage his health with regular wellness visits with your holistic or integrative veterinarian.

Tips for Encouraging Your Cat to Eat

If your kitty is eating processed pet food, my first recommendation is to try to slowly and safely transition her to a balanced, fresh, organic, non-GMO and species-appropriate diet. Whether her diet is fresh or processed, however, the goal should always be to make sure your cat eats something.

Unlike dogs and humans, it's dangerous for kitties to go any length of time without nourishment, as it can lead to a potentially fatal liver disease called hepatic lipidosis. Keeping your older cat well-nourished can require creativity along with some gentle prodding, and lots of patience. Things you can do to tempt her include:

  • Warming her food to bring out the aroma
  • Offering canned food with a strong smell or topped with a sardine (packed in water)
  • Offering new food from a paper plate in case she's developed an aversion to her food bowl for some reason
  • Offering a small selection of different flavors and textures of canned cat food or home cooked meat or bone broth
  • Enticing her with species-appropriate human food she has enjoyed in the past, such as warm baked chicken or salmon
  • If she's addicted to dry food and refuses everything else, try adding warm water to each meal or add an aromatic enticement like tuna juice, warm goat's milk or chicken broth

It's also important to make kitty's mealtime a very low-stress, pleasant experience. Make sure you feed her in a calm, quiet environment that is optimally comfortable.

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