Rapid weight loss in older dogs: What does it mean?

Is your beloved senior dog losing weight fast and you’re worried about the cause? Petwise shares why it might be happening and what you can do to help.

Your dog is a cherished part of the family. That’s why seeing it age and turn grey can be tough, especially if they start to look thinner.

Losing weight is sometimes nothing to worry about, but it can also be a sign of something serious. Discover what causes can make your dog shed the pounds faster as it gets older below.

Any obvious weight loss in senior pets calls for a visit to the vet. Protecting your hound with dog insurance lifetime cover means you won’t have to worry about medical bills if your canine needs treatment.

What age does a dog get old?

Do you know at what age a dog is considered old?

You may think that grey hairs and a wealth of medical issues signals your four-legged friend is entering its golden years, but they actually become a senior at what might seem a relatively ‘young’ age.

The exact age depends on their size:

  • Large dogs: 5-8 years old
  • Medium dogs: 7-10 years old
  • Small dogs: 9-12 years old

The older canines get, the more likely they are to suffer health issues and display certain behavioural problems, making it extremely important to protect their wellbeing with dog insurance lifetime cover. At Petwise, we have no upper age limit, so even the most senior animals can get coverage.

Do dogs get skinny when they’re old?

When canines begin to enter their later years, owners often see them put on weight rather than lose it. They exercise less due to low energy, and a slow metabolism can cause obesity in older pets, meaning your vet may recommend a change in diet.

However, shedding a few pounds throughout later life is just as normal, similarly to humans. When does it become something to worry about?

If your older furry family member starts to drop weight significantly, whether it’s fast or slow, it may be warning you that something isn’t right. The definition of significant weight loss in canines is 10% of their normal body weight.

Call your veterinarian for some advice or use our free 24-hour vet video consultation service if you have dog insurance lifetime cover with Petwise.

How can you tell your senior dog is losing weight?

Unless your four-legged family member loses a drastic amount of weight in just a few days, it can be difficult to tell it’s shedding the pounds.

When you see an animal daily, it makes it harder to notice subtle changes, so performing a regular Body Condition Score can help identify weight loss. You can, of course, get them to stand on the scales, but with extra wriggly pets, this is a challenging task!

Follow these steps to get a Body Condition Score (BCS) of your dog:

  1. Run your palms lightly along both sides of your pet, checking that the skin moves freely over its ribs.
  2. Run your hands across its back, feeling for your dogs’ spine and hip bones. You should be able to feel but not see them.
  3. Feel the base of your canines’ tail, checking that there is no fat build-up.
  4. When you feel under your pets’ tummy, it should go in and not bulge.
  5. Stand back and look at your dog from above and both sides. Their waist should be visible.

How do you work out their Body Condition Score? Rate your dog from 1-9, with 5 being the optimal size, using the following criteria:

Underweight (1-3): Dogs in this range will have a very tucked in waist, little to no body fat, and be visibly bony. Animals with a score of 1 are dangerously underweight.

Ideal weight (4-6): If your pet sits in this range, it’s a normal weight. You should see a visible waist and be able to feel their ribs and hips but not see them.

Overweight (7-9): Canines with this score have no visible waist and may have fat pockets around the neck, shoulders, and base of their tail. You can only feel their bones if you press down firmly. Pets with higher scores are considered obese.

If you don’t feel confident performing this exam by yourself, contact your vet. This is a routine visit and isn’t included in dog insurance lifetime cover, but non-emergency care is vital to spot potential health issues before they become worse.

A regular check to note their current score is an excellent way to spot significant weight loss and act fast to help your pet.

Why is my older dog losing weight?

Watching your loyal elderly dog become increasingly thinner is enough to make any pet parent worry. It might be a normal sign of them growing old, but it can hint at a serious problem with their health. Reasons for senior canines shedding the pounds include:

  • Ageing
  • Dental issues
  • Diabetes
  • Dehydration
  • Liver or gallbladder issues
  • Kidney disease
  • Heart failure
  • Urinary tract infection (UTI)
  • Cancer

We take a closer look at each one below and what other symptoms your dog might have to help you discover what’s causing their sudden drop in weight.


Like most of us, you probably know some elderly people who have put on weight as they aged, but also others who’ve lost some. Dogs are just the same, and may shed extra pounds due to muscle wastage, poor digestion, and having less appetite.

How do you know it’s a sign of a more serious issue rather than part of growing old? Your dog will need their Body Condition Score checked and to be weighed to see whether they’ve lost at least 10% of their normal weight.

These two figures can help identify major health concerns before it’s too late, giving you and your vet time to get your canine companion back to its usual self.

Dental issues

One of the most common causes of weight loss in senior pets is oral health problems. According to the Kennel Club, over 80% of dogs suffer a stage of gum disease before they are just 3 years old. As canines age, the likelihood of dental issues continues to increase.

Painful teeth and gums can mean your dog doesn’t want to chow down like it used to during meals, losing weight as a result.

Other symptoms of oral disease to watch for include:

  • Bad breath
  • Difficulty eating
  • Red and bleeding gums
  • Wobbly or broken teeth
  • Drooling
  • A preference for softer foods
  • Pawing at their face
  • Swollen face
  • Blood in the saliva

If you suspect your old hound is suffering as a result of its oral health, take them to the vet to prevent it from worsening. With dog insurance lifetime cover from Petwise, your pet can get dental care in case of an accident or illness as standard.


After reaching middle age, dogs are at a higher risk of developing diabetes, and one of the earliest signs of the disease is weight loss. When it can’t get energy from glucose, your diabetic dogs body begins burning stored muscle and fat.

Other signs that accompany weight loss and point to diabetes include:

  • General tiredness
  • Excessive thirst and urination
  • Urinary tract infections

If your vet diagnoses your animal with this condition, it can be controlled with a special diet and insulin injections to help maintain their blood glucose levels.


dehydrated dog drinking from water bottle

It might seem far-fetched to think your dog could be so dehydrated that they lose 10% of their body weight, but it can happen. As they age, canines become inclined to drink less, posing a danger to their health.

So if this is the root reason on why your dog keeps losing weight, you may also notice they urinate less and that it’s darker in colour than usual. They will seem very lethargic and possibly have rubbery gums.

Encouraging them to drink water is a good start, but if they’re still reluctant, try ice cubes, electrolyte drinks, and wet food that has more liquid. Always take them to the vet to check that it isn’t a sign of anything more severe.

Liver or gallbladder issues

Dramatic weight loss in your canine companion could mean something is wrong with its gallbladder or liver. These organs are both part of the digestive system and dropping a few pounds is one of the first symptoms.

It’s important to be alert and watch for other signs so your four-legged friend can make a full recovery. Liver disease, especially, comes with a range of other symptoms:

  • Vomiting
  • Diarrhoea
  • Less appetite
  • Pain
  • Fever
  • Yellowing eyes, gums and skin

Your vet may recommend medicine or surgery to treat the issue, depending on the severity. The faster you act, the less likely your dog will need surgical intervention. If you also happen to own a cat, check out our blog on how to care for a cat with a fever or how to help a cat with bloating.

Kidney disease

Your pets’ kidneys are another vital organ, and if they stop working like they should, it can wreak havoc on its body weight. Look out for loss of appetite, vomiting, and diarrhoea with lethargy and pale gums.

Sadly, if your dog has these symptoms, the disease is likely quite advanced, making it challenging to treat. This emphasises why keeping tabs on your beloved pets’ weight is so important to prevent serious illness.

In addition to dog insurance lifetime cover, consider a pet health plan to help spread the cost of routine check-ups and treatments to spot problems early on.

Heart failure

One of the earliest signs of heart disease in canines is weight loss. Taking your animal to the vet as soon as you notice it looking thinner could save its life. When caught early, lifestyle changes and medication can keep your hound comfortable.

Other symptoms that accompany weight loss during heart failure are:

  • Chronic coughing
  • Excessive restlessness
  • Difficulty exercising
  • Getting tired easily

Urinary tract infection (UTI)

UTI’s are fairly common in dogs, and the risk of one developing increases the longer your pet has to wait to go to the bathroom. An infection like this can cause a great deal of pain to your beloved pet and cause them to feel nauseous and vomit.

With feeling sick all the time comes a reduced appetite and then weight loss. If your dog seems disinterested at meal times, is dropping pounds quickly, and seems generally unwell, a UTI may be to blame.

These infections can be treated successfully with antibiotics when caught early. If you wait too long to take your four-legged family member to the vet, they may need more serious intervention and perhaps even surgery in the case of persistent infections.


Unfortunately, cancer is just as big a killer in canines as it is in humans. The first signs include weight loss, along with lethargy and less interest in their food. They may also develop unusual bleeding and have a distended tummy.

It’s important to examine your dogs’ body for lumps and bumps often to get it checked as soon as you notice one.

According to the PDSA, pets get all kinds of lumps throughout their life, and they aren’t always cancerous, but you should never take the ‘wait and see’ approach. 

Sometimes, canines don’t display many symptoms until the disease has reached an advanced stage. The location of the cancer determines the outlook and what treatment options your pet has.

If your loyal four-legged companion is terminally ill or you’ve recently lost a dog to a serious disease, it can be a difficult time.

With one of our dog insurance lifetime cover policies, you can get help with farewell costs and make use of the bereavement helpline to comfort you through this tough time.

How can I get an older dog to gain weight?

Once you know the cause of your senior pets’ dramatic weight loss, you and your vet can come up with a plan to slow down or stop the damage to their health.

If your dog is thinner due to its age and reduced desire to eat rather than something serious, the following tips can help you boost their appetite and waistline.

Buy premium food

As your ageing canines’ appetite decreases, so does their ability to absorb nutrients. This makes it essential to feed them the most nutrient dense, high quality meals possible. Their food needs to be above average in calories, protein, and fat to help them gain back a few pounds.

Speak to your vet about the best diet for your older pet. If they recommend a prescription food, your dog insurance lifetime cover may be able to help with a financial contribution.

Make their meals more appealing

Sometimes top quality isn’t enough to get your hound to lick their plate clean. Dry food can be tough for senior dogs to chew on, and perhaps it no longer appeals to their sense of smell. Encourage them to finish meals by:

  • Choosing smaller pieces
  • Soaking it in a warm bone broth for 10 minutes before they eat
  • Adding a spoonful of quality canned food or a tasty gravy
  • Mix in small pieces of cooked chicken or canned tuna
  • Add a bit of scrambled egg

You may also be able to get them to consume more calories across a day by giving smaller portions more often. It stops their stomach from overloading and lets them fully digest their previous meal before eating more.

Improve their digestive function

Just like with humans, your furry family members’ bodily functions start to slow down and become less efficient as they grow old. This can mean your dog struggles to digest their meals and absorb nutrients despite finishing their plate.

You can help their digestive system with supplements like prebiotics, probiotics and digestive enzymes.

Give them high calorie dog supplements

As your dogs’ body slows down and its muscles start to waste, they might need a nutritional boost to keep them strong. A calorie dense supplement can help and is easy to feed your pet as part of its meal. They usually come as a paste or liquid to mix with its food.

What to feed an older dog that’s losing weight

As mentioned above, your thinning dog needs premium food that’s dense in calories, fat, and protein. Aim for:

  • 35% more protein content
  • 15-20% higher fat content
  • Over 400 calories per cup

Complement their diet with supplements to boost their strength and help them absorb all the nutrients. Always consult a vet before adding supplements to your canine’s food.

If you’re worried about your animal’s diet, speak to your vet or call the Petwise 24-hour vet video consultation service for free. If you have a dog insurance lifetime cover policy with us, you may be able to get help with the cost of prescription food.

Why is my senior dog losing weight but still eating?

Not all dogs lose weight because of a reduced appetite. Sometimes, they finish all their meals but still seem to be shedding a significant amount of weight, making any pet parent concerned for their wellbeing.

It may be that they’re simply experiencing muscle wastage due to age or finding it hard to absorb all the nutrients. However, it could also signal one of the more serious health issues mentioned above. 

As soon as you notice your canine companion’s weight drop, take them to the vet. Many illnesses can be managed when caught early, but the outlook isn’t always so positive if you wait until their condition worsens.

Get lifetime pet insurance for your ageing dog

As your loyal canine ages, it needs all the love and care you can give to enjoy its golden years to the fullest. Your pet’s risk of losing weight increases as it grows older, and so does its chance of experiencing many other health concerns.

With the likelihood of more vet visits on the horizon, there’s never been a better time to protect your four-legged friend with dog insurance lifetime cover.

By choosing Petwise to cover your ageing companion, you get benefits like*:

  • Dental cover as standard
  • No upper age limit to joining
  • Contribution for senior food
  • Farewell cover and our bereavement helpline
  • Free access to 24/7 vet video calls

*Terms, conditions and limitations may apply

To give your senior canine the life it deserves, contact the Petwise team today to find the right dog insurance lifetime cover for your beloved pet.