Why Is Your Senior Cat Losing Weight? Get “The Skinny”

Portriat of happy senior woman with cat resting in bed at home.

Key Points

  • The energy needs of adult cats decrease as they age, and they need fewer calories.

  • It's common for some older cats to lose weight while continuing to eat normally.

  • Periodontal disease is one common reason your senior cat is losing weight.

  • Rapid weight loss in a cat might indicate a serious health condition.

Why is your senior cat losing weight? When you age, lots of things change. For one, you don't move as well as you once did, which may be from arthritic pain or because you get tired more easily. Your tastes change as well, and food doesn't taste the same as before. The same is true for felines as they age.

Cats tend to hide their symptoms when they don't feel well. This makes it more difficult for a caring pet parent to know what's happening. Regular vet visits help, but you know your cat. You recognize the difference between their normal behavior and something concerning.

Learn more about the potential causes of senior cat weight loss below and do something about it while there's still time.

black cat

What Age Is "Old" for a Cat?

This depends partly on the breed and the individual cat. Like humans, cats experience age-related issues at different times. Some may develop arthritic conditions or other health for cats issues earlier than others. Some cats considered "old" seem spry and youthful into their teens.

Life expectancy differs as well. Statistically, an indoor cat lives longer than an outdoor cat. Cats that roam freely outdoors get exposed to many more parasites and diseases than those that stay inside. They're also vulnerable to predators and automobiles.

Physiologically, at about age 10, cats' nutrition needs change. By age 12, they begin to experience physical, age-related symptoms. With advancements in veterinary care, it's not surprising for a cat to live to 20 years old.

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Your Elderly Cat Eats but Still Loses Weight

Most domesticated pets like routine. They do well eating the same kind of food every day, so it makes sense to feed them the same types of food and treats throughout their lives. When a cat reaches age 10, though, they need something different.

The experts at Catonsville Cat Clinic in Maryland say that the energy needs of an adult cat decrease by about three percent each year after they enter adulthood until about age 10, so they need fewer calories as they age.

"However, as cats get beyond the age of 10, their calorie needs increase again," the clinic states. "It turns out that if they are kept on the same diet as their younger years, their fat levels decrease, they lose muscle, and they have less energy."

This explains the gradual decrease in weight if your senior cat continues eating the same food as they always have. Many companies produce food specially formulated for the senior cat.

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Commons Reasons Senior Cats Lose Weight

All cats undergo changes in their nutritional needs, but there are other reasons a senior cat loses weight. Some of these are treatable, and some are even preventable. Prepare for these changes so you don't get caught off-guard.

Dental Issues

If you ever have tooth pain, you know how uncomfortable it is. Tooth and gum disease prevent your senior cat from enjoying their food. They don't want to bite down on anything hard, worsening the pain. Periodontal disease affects more than their teeth.

The buildup of plaque on the teeth may cause gingivitis, or inflammation of the gums. This condition is reversible, but if left untreated, bacteria builds up. This leads to a more serious form of gum disease called periodontitis. This may result in receding gums, infection, and/or tooth loss, sometimes requiring surgery.

As cats age, their immune system weakens and they don't fight off infections as well. A mouth infection may allow bacteria to get into the cat's bloodstream. This may carry infection to major organs like the liver or kidneys.

Brushing Your Cat's Teeth at Home

Try to prevent these issues by brushing your cat's teeth. Get a brush and toothpaste made especially for cats. A cat toothbrush has a small bristle head, so it isn't as intrusive. Cat toothpaste appeals to them, so they accept it more easily. It also doesn't have a foaming agent, which may cause choking.

Getting your cat to accept tooth brushing is a gradual process. First, allow your cat to familiarize themselves with the toothpaste and toothbrush. Let them smell and taste the toothpaste and sniff the brush.

Next, let your cat lick the toothpaste off your finger. Then put it on the side of their mouth. Do this over the course of a week. Since the toothpaste has flavoring appealing to cats, it isn't too difficult. Follow that with giving your cat a reward like their favorite treat. You want this process to be a positive experience.

The next step is to apply the toothpaste to one of your cat's canine teeth with your finger. Always follow with a reward. Do this every day for about a week. Once your cat is familiar with the toothpaste, put it on the toothbrush and let them lick it off.

Last, gently lift your cat's lip and position the brush at a 45-degree angle, aiming for the crevice between the teeth and gums. You have to move fairly quickly before your cat loses patience. Move your way around the upper and lower teeth on both sides of their mouth.

The direction of motion is unimportant. The main goal is to disrupt the plaque so there's no buildup. Always check for signs of concern like blood on the brush, swelling, or redness of the gums. If you see anything concerning, make an appointment with your vet.

If your cat has tooth pain, wet food is much easier on their teeth and gums. There are also tasty paste treats that come in tubes or packets.

older cat

Decreased Sense of Smell

As cats age, they sometimes begin to lose their senses, like eyesight and sense of smell. If your cat is eating less, they may be unable to smell their food. This isn't as common as dental issues.

Fish flavors have a more pungent odor. If your cat's sense of smell merely diminishes, stronger-smelling food may be enough. Having them on a schedule might benefit them as well. If they eat at the same time every day, they may eat out of habit, even if they don't smell it or feel hungry.


When a cat gets older, they're unable to groom themselves as effectively as they once did. They may also become fussier and groom more often. This leads to the development of more hairballs.

If your cat doesn't digest their hair, it clumps and forms hairballs that they cough up. If they vomit frequently, this may lead to weight loss. In some cases, hairballs cause loss of appetite, which also leads to weight loss.

In a 2016 article from the Cornell Feline Health Center at Cornell University, the center writes, "Daily brushing or combing removes loose hairs, preventing them from being swallowed and forming hairballs. Brushing also stimulates blood circulation and sebaceous gland secretions, resulting in a healthier skin and coat."

Brushing is particularly crucial for cats with long or coarse hair. If your cat isn't used to brushing, you may have to introduce it gradually. Choose a soft-bristled brush, as a senior cat's skin may be thin and more sensitive. Brushing also creates an affectionate bonding experience between you and your cat.


Worms are parasites that live off of nutrients in your cat's diet. If your cat eats meals regularly but still loses weight, check their stool for roundworms, hookworms, tapeworms, or eggs.

If your cat has worms, you probably see them licking their rectum more frequently. You may see whole tapeworms sticking out of the cat's rectum. You find some parasites only through fecal testing.

Over-the-counter dewormer exists, but if you aren't sure which type your cat has, your vet can perform an examination. They prescribe a deworming medication appropriate for the specific variety of parasites.

Other Causes

Without a thorough examination, the cause of your senior cat's weight loss may be unclear. Besides dental issues and loss of the sense of smell, there are several possibilities.

David A. Williams, MA, VetMB, Ph.D., DACVIM, DECVIM, studied at the School of Veterinary Medicine at the University of Illinois. Williams published a paper identifying the causes of weight loss in senior cats.

Among common causes, Williams lists chronic renal disease, diabetes mellitus, hyperthyroidism, inflammatory bowel disease (IBD), exocrine pancreatic insufficiency, in addition to dental problems. He says a veterinarian identifies most by a physical examination or routine lab testing.

There are other unknown causes, like the decline in food digestibility. In these cases, Williams suggests a low-carb, high-protein diet and supplements, including prebiotics, probiotics, vitamin E, and antioxidants.

If your senior cat loses a concerning amount of weight in a short amount of time — no matter what the expected reasons — take them to the vet to get a diagnosis. Rapid weight loss usually indicates a more serious problem.

white cat scratching

How Skinny Is Too Skinny?

Since every cat is different, they may go through the cat aging process at different rates. A gradual decrease in weight is difficult to spot unless you keep diligent records and check them regularly for changes.

A cat is too skinny if their ribs are easily visible through their skin. This is easier to see on a cat with short hair. If your cat has thick fur, feel their sides to see if there's at least a thin layer of fat covering their ribs.

You see your cat losing weight in their hindquarters if you see their waist very obviously behind their ribs when looking down at their back.

What To Feed an Older Cat

Low-carb, high-protein diets are ideal for senior cats that are underweight. Food with fish as the main ingredient contains omega-3 or omega-6 fatty acids that are good for their health. Your vet may recommend a food formulated especially for senior cats. These are more digestible and palatable.

Your vet might also recommend kitten food that is higher in protein. If your cat has trouble eating food because of dental issues, kitten milk replacer is another option.

There are high-calorie supplement gels that help with weight and nutrition. Prebiotic and probiotic supplements come in powder form that you sprinkle on their food.

Adopting a Senior Cat

Older felines have their issues but need loving owners like any other cat. Be aware of their needs and prepared for the changes they go through.

On May 24, 2023, a shelter volunteer posted a video on TikTok of a senior cat named Jeff. He cries and greets her every morning from the window of his cage. Three days later, the worker posted a video saying that they have applications for his adoption. The latest video update of Jeff says that he maxed out his adoption applications.

Go to your local shelter to find a senior cat that needs care. These cats should have a comfortable place to call home for the rest of their lives. Workers and volunteers provide care and affection, but each person has a limited amount of time for each pet when surrounded by so many animals.

If your adopted cat is underweight, visit your vet for advice on how to deal with their specific issue.

older asian woman with cat

Underweight, but Not Underloved

Older cats provide great companionship, so don't discount them. Some of their age-related symptoms are reversible and, in some cases, preventable. If your cat enters their senior years, take measures to prepare them.

If your senior cat loses weight but acts normally, they may hide other symptoms. Cats are good at that. Regular vet visits are essential, but your own examinations are just as crucial. Communicate with your vet about all the signs you see in addition to their weight loss.

Make your old cat as comfortable as possible. They deserve the same amount of love and affection as any other feline.

Visit CattitudeDaily for more great information on taking care of your feline and health tips for senior cats.

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