Do Cats Lose Weight as They Age? The Truth About Senior Felines’ Changing Bodies


Weight loss is a common issue in senior cats as they reach 11-14 years of age. As cats get older, various factors can cause them to gradually lose weight, or experience more sudden or rapid weight loss. It’s important for cat owners to monitor their senior cat’s weight and understand the potential causes behind weight changes in older cats. Gradual weight loss in senior cats can indicate underlying health issues, while rapid weight loss requires prompt veterinary attention. This article will provide an overview of normal aging changes affecting weight, medical conditions that can lead to weight loss in senior cats, tips for maintaining healthy weight, when to seek veterinary care, and the prognosis for senior cats struggling with weight loss.

Normal Aging Changes

It’s common for older cats, usually over the age of 11, to experience a decreased appetite as part of the normal aging process. As cats get older, their sense of smell can diminish, making food seem less appealing. Additionally, their stomach may empty more slowly, causing them to feel full more quickly. Older cats also tend to be less active and have a slower metabolism, so they require fewer calories. A mild decrease in food intake, such as eating 25-50% less than when they were younger, can be normal for senior cats. However, a dramatic decrease in appetite or refusal to eat are not typical and warrant a veterinary visit. It’s important to monitor any changes in eating habits closely in older cats.

Underlying Medical Conditions

There are several common medical conditions that can cause weight loss in senior cats:

Hyperthyroidism – An overactive thyroid gland leads to a faster metabolism and weight loss despite a normal or increased appetite. It occurs in 10-15% of cats over 10 years old. Symptoms include increased appetite, hyperactivity, vomiting, diarrhea, and unkempt fur coat in addition to weight loss (Source).

Kidney disease – Damaged kidneys can’t concentrate urine properly leading to increased thirst and urination. Toxins build up in the bloodstream causing nausea, vomiting, and weight loss. Kidney disease affects more than 1 in 3 cats over 15 years old (Source).

Diabetes – Insufficient insulin leads to high blood sugar and the breakdown of fat and protein stores causing weight loss. Increased thirst and urination are also common. Diabetes affects 1 in 100-500 cats (Source).

Dental Disease

Dental disease is extremely common in senior cats, with studies reporting a prevalence between 50-90% in cats over 4 years old (source). Dental diseases like periodontal disease and tooth resorption can cause significant pain and discomfort in a cat’s mouth.

Periodontal disease involves inflammation and infection of the tissues surrounding the teeth. It begins with a buildup of plaque and tartar on the teeth that harbors bacteria. The bacteria cause inflammation and irritation of the gums termed gingivitis. As the disease worsens, it spreads below the gumline affecting the periodontal ligament and tooth roots (source).

Tooth resorption is another common dental problem in older cats where the body breaks down and dissolves the mineral structure of the teeth. This can expose the sensitive inner tooth structures and nerves causing significant pain. Resorptive lesions are often found at the gumline of the teeth.

The painful inflammation, infection, and erosion of tooth structures caused by these dental diseases can make it difficult for a cat to eat. This may cause weight loss. Proper diagnosis and treatment of dental disease by a veterinarian is important to manage pain and prevent complications.

Digestive Issues

As cats age, their digestive systems can become less efficient at absorbing nutrients from food. This condition is known as malabsorption and can lead to weight loss in senior cats (1). Malabsorption is often caused by inflammatory bowel disease (IBD), which involves chronic inflammation of the gastrointestinal tract. IBD is one of the most common causes of vomiting, diarrhea, and weight loss in older cats (2).

IBD prevents the small intestine from properly digesting and absorbing nutrients. As a result, older cats with IBD will pass poorly digested food in their stool. They may have frequent loose stools, constipation, vomiting, loss of appetite, and subsequent weight loss (3). IBD can be challenging to diagnose and is confirmed through intestinal biopsies taken during endoscopy. Treatment for IBD involves anti-inflammatory and immunosuppressive medications to control the inflammation and allow the intestinal lining to heal.

Managing malabsorption and IBD in senior cats requires a combination of medications and a highly digestible diet formulated for gastrointestinal health. These specialized diets are crucial for cats with malabsorption to maximize nutrient absorption from their food (1). With proper treatment and nutrition, many cats with digestive issues can regain normal body weight and condition.


Cats with cancer often experience weight loss for a variety of reasons. Cancerous tumors increase the body’s metabolic needs, often requiring more calories to support their growth (Feeding Your Cat During Cancer Treatment). At the same time, cancer can suppress appetite and lead to muscle wasting, resulting in reduced food intake and weight loss (Feeding the Cat with Cancer). Certain cancers like lymphoma and mammary cancer are more likely to cause weight loss in cats.

Additionally, cancer weakens the immune system and can make cats more prone to developing secondary health issues like dental disease, intestinal parasites, kidney disease, and hyperthyroidism, all of which can lead to weight loss. Cancer treatment side effects like nausea and mouth sores can also reduce appetite. Older cats are at increased risk for developing various forms of cancer, so any unexplained weight loss in senior cats warrants a veterinary visit for diagnostic testing.

Behavioral Changes

As cats age, it’s common for their behavior to change in various ways. One of the most noticeable changes is increased vocalizing and “crying out” for reasons that may not be apparent. According to the ASPCA, older cats may vocalize excessively for a number of reasons, including disorientation, loss of hearing and pain due to medical conditions.

Disorientation is another common behavioral change in senior cats. The Cornell Feline Health Center notes that similar symptoms may be seen in elderly cats including wandering, excessive meowing, apparent disorientation, and avoidance of social interaction. Disorientation can cause cats to seem confused, lost, or unsure of where they are. It’s important to keep their environment consistent and comfortable to reduce disorientation episodes.

Tips to Maintain Healthy Weight

As cats age, it’s important to monitor their weight and make adjustments as needed to keep them at a healthy weight. According to Small Door Veterinary, senior cats should be weighed at least every 6 months. Significant weight loss or gain may indicate an underlying health issue.

Adjusting your cat’s diet is one of the best ways to maintain their weight. Feed a high-quality senior cat food formulated for your cat’s age and activity level. Wet food can help add calories for underweight cats. Overweight cats may need portion-controlled meals or a weight management cat food. Consult your vet on the ideal diet for your senior cat.

Keeping your senior cat active will also help maintain muscle and a healthy weight. Provide engaging toys, scratching posts, cat trees, and windows with views of birds and squirrels. Brush your cat daily to stimulate circulation. Short, gentle play sessions will encourage exercise. Just be sure to monitor your cat’s mobility and don’t push beyond their physical limits.

When to Seek Veterinary Care

It’s a good idea to bring your cat to the veterinarian if you notice weight loss, especially if it’s sudden or rapid. According to PetMD, weight loss of more than 10% in a few weeks or 20% over a few months should be evaluated. Even slower, steady losses in weight warrant a veterinary visit.

Along with weight loss, watch for other concerning symptoms that signal an underlying issue. These include increased thirst and urination, vomiting, diarrhea, decreased appetite, lethargy, poor coat condition, and hunched posture. Cats also mask illness very well, so noticeable symptoms likely mean your cat is already quite sick. Don’t hesitate to seek veterinary care if you notice anything out of the ordinary.

Some key things the veterinarian will look for are dental disease, cancer, hyperthyroidism, diabetes, kidney disease, intestinal parasites, and digestive issues. Diagnostic tests like blood work, urinalysis, imaging, and biopsies can help uncover the root cause of weight loss.

Early veterinary intervention maximizes the chances of successful diagnosis and treatment. Don’t delay in bringing your cat in if you have any concerns about weight loss or other symptoms.


The prognosis for a senior cat losing weight depends greatly on the underlying cause. If there is an identifiable medical condition causing the weight loss, such as hyperthyroidism, kidney disease, or cancer, the prognosis will depend on the specific diagnosis and how treatable it is.

For cats losing weight due to aging changes like decreased appetite or activity, the prognosis is generally good if the weight loss can be managed through diet, supplementation, and other supportive care. However, significant unintended weight loss can negatively impact quality of life and be difficult to reverse in elderly cats.

With prompt veterinary care and owner vigilance, many causes of senior cat weight loss can be addressed to extend and improve life. Cats losing weight for no clear reason require close monitoring and care. Overall the prognosis ranges from grave to good based on the cat’s individual circumstances.

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