Weight loss in older dogs: causes, concerns, and caring

If you’re reading this, you probably share your life with a senior four-legged friend who’s been losing weight lately. First things first, take a deep breath and know that you’re not alone. I know that your dog is more than just a pet; he’s family. And when a family member starts to show signs of change, it’s only natural to seek answers and solutions. 

First, you need to understand that weight loss is a symptom, not a disease. It’s a sign that something is not quite right. 

Broadly speaking, there are two possible reasons why is your old dog losing weight. Either your pup needs a different diet, or he’s suffering from an underlying health issue. In any case, you need to find out why it’s happening and address it. As a veterinarian, my best advice right now is to take your pet to a vet. 

However, I will also encourage you to learn more about this issue. By understanding why it’s important to monitor your dog’s weight and how it influences your pet’s health, you can take better care of your senior friend. And that’s why I’m here ☺️

Ready? Let’s dive in! 💕

This post may contain affiliate links, which means I may receive a commission, at no extra cost to you, if you make a purchase through a link. Please see my full disclosure for further information.

While I am a veterinarian, this article is not intended to replace professional veterinary advice. If you have any medical concerns about your pet, consult your vet immediately. Always seek professional assistance if you are unsure of your pet’s health.

old cocker spaniel lying on a soft dog bed

Understanding normal weight and weight loss in senior dogs

As your furry friend grows older, you need to know what constitutes a healthy weight for him. 

While the ideal weight can vary from one dog to another depending on factors like breed, size, and overall health, understanding the general principles of maintaining a proper weight in aging dogs is paramount. 

And when it comes to an aging dog losing weight, early detection is key. 

Recognizing the signs of weight loss in older dogs

It can be pretty obvious if your pup suddenly loses a few pounds. However, slow gradual weight loss can be much harder to detect. Most pet owners don’t monitor their pet’s weight, and it’s easy to miss these subtle changes in your dog’s appearance until they become more pronounced.

Knowing the physical signs to look for can help you realize there’s a problem and address the issue promptly. 

Physical signs of weight loss in dogs:

  • Visible ribs and spine: One of the most noticeable physical signs of weight loss in elderly dogs is the visibility of their ribs and spine. While a healthy dog should have a layer of fat covering these bony structures, significant weight loss can lead to a pronounced, easily seen ribcage and spine. Running your hands along their sides should not make these bones overly prominent.
  • Prominent hip bones: Another physical indicator is the prominence of hip bones. Normally, you should be able to feel your dog’s hip bones when you gently press, but they shouldn’t jut out visibly. In an underweight dog, these bones become more prominent, indicating a loss of muscle and fat.
  • Muscle wasting: Weight loss doesn’t just affect fat stores; it can also lead to muscle wasting. You may notice that your aging dog’s muscles appear thinner, less toned, or less firm. This can be particularly evident in the thigh and shoulder muscles.

Monitoring your dog’s weight

To monitor your dog’s weight, it is important to establish a baseline and track changes over time. You can do this by weighing your dog regularly and keeping a record of their weight.

However, I know that regularly weighing a dog at home is sometimes almost impossible, especially if you have a large or giant breed 😃 In this case, using a BCS will help you spot early changes in your pup’s weight without having to put him on a scale 👇

Body condition scoring system

The body condition scoring (BCS) system is an invaluable tool in assessing a dog’s weight and overall health. This system, typically rated on a scale of 1 to 9, with 1 being emaciated and 9 being obese, helps owners and veterinarians gauge a dog’s condition.

 It takes into account both visual and tactile factors, such as the visibility of ribs, spine, and pelvic bones, as well as the amount of fat covering the body.

Ideally, a healthy dog should fall within the 4 to 5 range on this scale, where you can feel the ribs without excessive fat covering. A score below 4 indicates the dog is underweight, while a score above 5 suggests they are overweight. 

Here’s a detailed guide on how to use Body Condition Score for pets.

old dog standing in a meadow

The most common reasons for weight loss in old dogs

There are several reasons why is your old dog losing weight. 

As dogs age, they become more susceptible to various health conditions which can directly result in weight loss. On top of that, their metabolism changes, and their ability to absorb nutrients from their food starts to decline. 

Basically, weight loss in older dogs can be attributed to insufficient diet or underlying health problems. 

Sudden weight loss can indicate a serious problem and requires immediate veterinary attention.

Weight loss in senior dogs can be caused by a variety of medical conditions, including:

Dental disease:

Dental problems are one of the most common causes of weight loss in older pets. They can significantly impact a dog’s ability to eat comfortably, leading to weight loss. 

As dogs age, dental issues such as gum disease, tooth decay, and missing teeth become more common. Painful oral conditions can discourage them from chewing their food properly, causing them to eat less or avoid food altogether. 

Learning the signs of dental problems in dogs, regular dental check-ups, and proper oral hygiene are essential to keep your dog healthy in his old age.

Chronic kidney disease:

Chronic kidney disease is a common health problem in senior animals. Sadly, it often goes unnoticed, since kidneys have a huge ability to compensate for the loss of function. 

Often we see clinical signs only after a significant decrease in renal function. The signs of chronic kidney disease might include lack of appetite, weight loss, increased thirst, increased frequency of urination, and diarrhea or vomiting. 


Hyperthyroidism is a condition that occurs when the thyroid gland produces too much thyroid hormone. The most common symptoms are weight loss, increased appetite and thirst, and frequent urination.


Cancer is another prevalent health condition seen in older dogs, often associated with weight loss. Given the multitude of cancer types, I won’t delve into specific details within this post. However, it’s worth noting that as dogs age, their risk of developing cancer increases significantly.

Diabetes mellitus:

Diabetes mellitus is a condition that occurs when the body is unable to properly regulate blood sugar levels. Common signs of diabetes are weight loss, increased thirst, frequent urination, and increased appetite. 

Intestinal parasites:

Internal parasites like worms (e.g., hookworms, tapeworms) can cause gradual weight loss by robbing your dog of vital nutrients. Routine deworming and regular fecal examinations can help prevent and detect parasitic infections promptly.

Gastrointestinal disorders:

Infections, chronic gastrointestinal problems, liver disease,  inflammatory bowel disease, and other diseases affecting the gastrointestinal tract can all result in rapid weight loss. However, there are usually other signs as well, like vomiting, diarrhea, or fever. 

Insuffcient nutrition:

Sometimes older dogs start losing weight due to changes in their metabolism. They are no longer able to absorb all the nutrients they need from their diet and start losing muscle mass and body weight. This is the main reason why your geriatric dog needs a nutrition-rich diet to keep his resting body weight. 

Chronic pain and Arthritis:

I have to mention arthritis because it’s so prevalent in the senior canine population. While arthritis doesn’t directly lead to weight loss, it can contribute to slow loss of weight and muscle mass. 

Any type of chronic pain has a severe impact on a dog’s overall well-being, as well as his emotional state. It can also influence his appetite. 

As you can see, weight loss is a broad symptom that can stem from various underlying health conditions. Thus, if you notice your senior dog shedding pounds, take him to a vet for a thorough examination. 

Your veterinarian will determine the underlying health problem and develop a specific treatment plan for your pup.

Infographic: Most common causes why is an old dog losing weight

Other symptoms and signs to look for

Unexplained weight loss in senior dogs that is accompanied by other symptoms is usually a sign of underlying health issues. 

Here are some symptoms and signs to look for if your old dog is losing weight:

  • Decreased appetite
  • Increased drinking
  • Bad breath and other signs of dental problems
  • Vomiting, diarrhea, or constipation
  • Frequent or excessive urination
  • Shortness of breath
  • Lethargy
  • Fever
  • Chronic cough
  • Lumps, bumps, or swelling

If your dog is experiencing any of these signs, it’s important to take him for an evaluation. 

senior dog lying down, text reads If your old dog is losing weight, the best thing you can do is to take him to a vet

Diagnostic procedures and treatments

When your senior dog experiences weight loss, it’s essential to identify the root cause to ensure prompt and effective treatment. This means taking him to the vet as soon as possible.

Diagnostic procedures:

Your veterinarian will assess your dog’s overall health, consider his medical history, and perform a comprehensive physical exam. He may also order further diagnostic tests to help determine the underlying cause of the weight loss.

The most common diagnostic tests are blood work,  x-rays or ultrasound, and fecal examination. 

  • Blood work: Blood tests are invaluable in diagnosing a wide range of health issues. A complete blood count (CBC) and blood chemistry panel can reveal information about organ function, detect signs of infection, and assess for conditions like diabetes, kidney disease, and liver dysfunction. Elevated or abnormal values in these tests can provide critical insights into the cause of weight loss.
  • Imaging (X-rays, Ultrasound): In many cases, imaging studies such as X-rays and ultrasound are essential to visualize internal structures and identify abnormalities. X-rays are useful for assessing bones, joints, and the chest cavity, while ultrasound can provide detailed images of soft tissues and organs. These tests are instrumental in diagnosing conditions like tumors, gastrointestinal issues, and heart disease.
  • Fecal examination: A fecal examination is a simple yet valuable diagnostic tool to identify the presence of internal parasites. Even minor infestations can contribute to weight loss, so this test is routinely performed to rule out parasitic infections as a cause of your dog’s symptoms.
  • Surgery or biopsy: In some cases, surgery may be necessary to diagnose or treat the underlying condition. For example, if your dog has a tumor, surgery may be necessary to remove it. 

These tests can help identify any underlying health conditions that may be causing weight loss or other signs.

Creating a treatment plan:

The treatment your dog needs depends on what’s causing their weight loss. 

If it’s due to something less serious like a dental problem or an infection, treatment generally revolves around targeted interventions. This could be a dental cleaning and possible extractions for dental issues or a prescribed regimen of antibiotics or other medications to combat infections.

However, when the weight loss is attributed to a more severe and potentially life-threatening condition, such as cancer or kidney disease, your dog will need a more aggressive and comprehensive treatment. In any case, please follow your vet’s medical advice. 

Your dog’s treatment plan will be designed to address his specific problem. Your vet will guide you through the options and help you decide what’s best for your dog’s health.

Overall, when you notice that your dog is losing weight, it’s important to take him to a vet as soon as possible. 

Nutritional requirements of senior dogs

As our furry friends get older, they need different kinds of food to stay healthy and happy. You probably know that puppies have different nutritional needs, but the same is true for senior dogs. 

Your dog’s body undergoes various physical and metabolic changes. The ability to ingest all necessary nutrients declines with age. This means your pup will need a few diet changes to stay healthy. Why? Because proper diet and nutrition are essential for maintaining a healthy weight, preventing illness, and improving overall well-being. 

Choose a nutrient-rich, high-quality, and highly digestible diet with all necessary supplements that support the needs of senior dogs.

So when you want to choose the best diet for your older dog, this is what you should consider:

High-quality proteins

Protein remains a vital component of senior dogs’ diet. In fact, it becomes even more crucial as they age. High-quality, highly digestible protein sources help maintain muscle mass and support overall health. 

Look for dog foods with high-quality and easily digestible proteins.

Reduced caloric intake

One of the most notable changes in older dogs is a decrease in activity levels and metabolism. As a result, they require fewer calories than their younger counterparts to prevent weight gain.

However, if your dog is losing weight, he might need a bit more calories in his diet to help him maintain a normal body weight. In this case, I would strongly advise you to consult your veterinarian to determine the appropriate daily caloric intake for your senior dog. I don’t want you to end up with an overweight dog 😊

Controlled fat intake

Most senior dogs need less fat in their diet compared to their younger counterparts. A lower fat content helps prevent obesity and reduces the strain on aging organs, particularly the liver and pancreas. 

But again, if your dog is losing weight instead of gaining weight, he might need a special diet to help him keep a healthy body mass. Fats in your dog’s diet should come from healthy sources like fish oil.

Joint health support

Senior dogs often suffer from arthritis, hip dysplasia, or other mobility-related conditions. You can find several supplements that can help to alleviate discomfort and maintain mobility.

Consider feeding your senior dog foods enriched with glucosamine and chondroitin sulfate. These compounds can help protect and repair cartilage in their joints.

Additionally, omega-3 fatty acids found in fish oil can reduce inflammation and improve joint function.

Health conditions

Many senior dogs have health conditions that require a specific diet. For example, dogs with kidney disease need a diet that is low in protein and phosphorus, while diabetic dogs need a low-carbohydrate diet. Talk to your vet about your dog’s specific needs!

Proper diet and nutrition are essential for maintaining a healthy weight, preventing illness, and improving overall well-being, especially in your pup’s senior years. Feeding your dog a high-quality food that is specifically formulated for seniors can help ensure that your pup is getting all the nutrients he needs.

Tailoring a care plan for your senior dog

It’s important to tailor a care plan that addresses the specific needs of your aging dog to ensure he remains healthy and comfortable.

Consult with a veterinarian

The first step in developing a care plan for your dog is to consult with a veterinarian. He can assess your dog’s overall health, determine the cause of the weight loss, and create a specific treatment plan. 

Adjust your dog’s diet and feeding schedule

Once the cause of your dog’s weight loss has been determined, you can work with your veterinarian to adjust their diet and feeding schedule accordingly.

  • Choosing the right dog food: It’s important to feed your senior dog a high-quality, nutrient-dense dog food that is specifically formulated for his age and needs. Consult your veterinarian for recommendations on brands and formulations tailored to your dog’s unique needs.
  • Feeding strategies: Consider dividing meals into smaller, more frequent servings if your pup doesn’t want to eat. For dogs with dental issues, transitioning to soft or wet food can make eating easier and more enjoyable. You can also pour water or broth over your dog’s dry food. Be mindful of portion control to prevent overfeeding or underfeeding. Talk to your vet about the amount of food your dog needs per day.

Take care of your dog’s teeth

Maintaining good dental health is integral to your dog’s overall well-being. Regular dental check-ups and professional cleanings can prevent dental diseases, and spare your pup from unnecessary pain. In addition to professional check-ups, your dog also needs proper dental care at home. Certified dental treats might also be a good idea 🙂

Manage the underlying medical condition

If your dog’s weight loss is linked to an underlying medical condition, please always adhere to prescribed medications and supplements as directed by your veterinarian. 

Make sure you follow your vet’s instructions about proper administration and dosing. 

Keep your vet informed of any changes in your pup’s condition. 

Provide adequate exercise and mental stimulation

Exercise is important for dogs of all ages, but it’s especially important for aging dogs. Regular exercise can help maintain muscle mass and keep your dog at a healthy weight. 

Gentle walks, low-impact activities, and mobility exercises can help maintain muscle mass and overall vitality. Mental stimulation through puzzle toys, interactive games, and training sessions keeps their minds sharp and wards off boredom and depression. 

It’s important to tailor exercise to your dog’s individual needs. Your veterinarian will help you determine an appropriate exercise routine.

Monitor your dog’s health

As your dog ages, it’s important to monitor his health closely. This involves regular check-ups with a veterinarian, monitoring his weight and BCS, and keeping an eye out for any changes in behavior or appetite. By staying on top of your dog’s health, you can address any issues that arise before they become more serious.

As your dog ages, his needs may change. Adapt your care plan to accommodate any new challenges or requirements that arise, such as mobility issues or changes in behavior.

By following (and adapting) a specific care plan you can help your aging dog maintain a healthy weight and live a happy life 🙂

PS: If you are as crazy about animals as I am and want to get more pet health tips, subscribe to my newsletter! Today you will get a free pet planner as a bonus 

What to read next:

Leave a Reply

Your email address will not be published. Required fields are marked *