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As with any animal, it is important that your dog maintains a healthy weight to give them the best chance of living a long and healthy life. Noticing that your dog is losing weight can be alarming and worrying, and trying to find out why they are losing weight isn’t always that straightforward. In this blog, we take a look at the potential causes of weight loss in dogs, how you can tell if your dog is losing weight and what you should do in the event of unexpected weight loss.  Our Dog Gold Plan is a great preventative option with regular health checks included within the subscription fee.   If you have any immediate concerns please book an appointment online for the soonest availability that works for you.

What might be causing my dog to lose weight?

There are many reasons that could be causing your dog to lose weight – some serious and some more easily rectified. For this reason, is it vitally important that you bring your dog for an appointment at Knutsford Vets if you notice that they are losing weight. Here are some of the causes of weight loss often seen in dogs:

Poor or unsuitable diet

Just like with any animal, it is important that your dog has a high quality diet that provides them with the calories and nutrients they need to maintain an optimal weight. You should assess whether your dog is getting enough calories for their size and level of exercise. For example, your dog may not be receiving enough calories if you have increased their exercise without increasing their food, or if you have another pet who may be stealing your dog’s food, meaning your dog is eating less than you think they are.

Dental Problems

We all know that toothache makes it almost impossible to eat solid foods, and this is no different for your dog. Dogs are prone to dental issues such abscesses which cause severe pain and prevent the dog from eating. In these cases, your dog will require antibiotics from the vet and may even need the tooth removing in severe cases.

Gastrointestinal diseases

Excessive vomiting and diarrhoea can both cause your dog to lose weight. A number of gastrointestinal disorders can cause these symptoms, so your dog will require a thorough examination to determine the cause. Examples of some gastrointestinal diseases include stomach ulcers, liver disease and Irritable Bowel Disease.

Hormonal problems

Hormonal imbalances or problems can cause a dog to lose weight. For example, Diabetes prevents your dog from being able to control their blood sugar levels, causing rapid weight loss, excessive urination and increased drinking. It also causes changes in appetite, so your dog may have an increased appetite but still lose weight.

Addison’s Disease, which causes a lack of steroids in your dog’s body, is another hormonal problem in dogs that may present with weight loss, lethargy, diarrhoea, and vomiting.

Kidney disease

Kidney disease won’t necessarily cause your dog to lose weight straight away, but weight loss is commonly seen with chronic incidents of kidney disease. Both fat and muscle can be affected, leading to your dog looking emaciated. Other symptoms of kidney disease include smelly breath, diarrhea and vomiting.


Worms can become a serious problem for dogs if they are not routinely medicated against. Worms can live in the dog’s digestive system and deprive the dog of nutrients by consuming the food the dog eats before the dog can properly digest it. Luckily, worms can be easily treated through a range of different medications, and regular preventive worming will help your dog from developing a large worm burden. Speak to us for advice on worming.

Stress and anxiety

Stress and anxiety can significantly affect a dogs appetite. Dogs are highly perceptive to change and some dogs do not cope as well with change as others. You should consider whether there have been any recent changes to your dog’s lifestyle that could be making him anxious – for example, a new pet, a new baby or a house move.


Cancers often cause weight loss and muscle wastage in dogs. This can come on very suddenly or be a gradual process. Cancer is generally more common in older dogs and can be life-threatening.

Heart disease

Weight loss in adult dogs or stunted growth in puppies could be a sign of heart disease (Cardiac Cachexia). In adult dogs, you may notice significant muscle loss, particularly in the muscles over their back, shoulders, hindquarters or on the top of their head. As this progresses, you may also notice your dog become weaker and lethargic.

How to spot signs of a dog losing weight

When you are used to seeing your dog everyday it can be difficult to spot subtle changes in their weight. However, spotting weight loss early is important so that the underlying issue can be identified as soon as possible, which will minimise the risk of it turning into something more serious. Therefore, you should build regular weight monitoring into your healthcare routine for your dog so that you will quickly identify any changes. The two most effective ways to do this through regular weighing and by performing body composition checks. We will explain how to do this below.

Weigh regularly

If your dog is small enough for you to carry, you can try to weigh them using the bathroom scales. First of all, weigh yourself without the dog, and make a note of the weight. Then, pick your dog up and stand on the scales, which will give you a combined weight for you and your dog. You can then subtract your weight from the combined weight to work out your dog’s weight.

If your dog is very small, you may need to use baby scales to be able to notice the weight loss as the actual weight change will be smaller than for a bigger dog and so may not be registered on a standard bathroom scale. On the other hand, if you have a very large dog, you may need to invest in dog specific scales to be able to safely weigh him at home. If you find the above difficult, call us and we can organise a time for you to attend the clinic where we can weigh your dog for you.

Our helpful video on weighing your dog can be seen below.

Perform body composition checks

A body composition test allows you to determine how much excess fat your pet is carrying without the need for scales, so they are a great way to monitor your dog’s weight in-between visits to the surgery. To assess your dog’s body composition, there are three checks that you need to make:

  1. Rib check. Run your hands over your dog’s ribs. If you can feel their ribs easily with little to no fat covering then your dog is underweight, whereas if you can hardly feel their ribs under the fat then it’s time for them to lose a few pounds!
  2. Profile check. Visually assess your dog from the side. Signs of them being underweight include the stomach appearing to be ‘tucked up’, and some of their prominent bones being visible such as the pelvis and ribs.
  3. Overhead check. Look down on your dog from above. If they have an exaggerated waistline and visible ribs then they may be underweight.

You should repeat these checks regularly so that you can quickly identify if your dog is losing weight.

What should I do if my dog is losing weight?

As we have explained in this blog, there are many potential reasons as to why your dog is losing weight, some of which can be life-threatening. Therefore, the first thing you should do if you notice your dog is losing weight is book an appointment at Knutsford Surgery so that your dog can receive a thorough examination and any more serious problems can be ruled out.

Your vet will conduct a series of tests to determine what is causing your dog to lose weight and will then provide you with a tailored treatment schedule to help your dog get back to their optimum weight. This may include altering their diet to a higher calorie food, or a food that is gentle on the digestive system if gastrointestinal problems are diagnosed. Similarly, if worms are thought to be the cause of your dog’s weight loss, you will be prescribed a course of de-worming treatments.

After your appointment, you should use the weight monitoring processes that we discussed earlier in the blog to frequently reassess your dog’s body weight and ensure that the treatment plan is having the desired effect. If you have any concerns or your dog continues to lose weight, bring them back to the surgery for a follow-up appointment.

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