Is my dog underweight? 🐶⚖️

Dog with food bowl

Just like extra fluff can be a concern, being too thin isn’t always harmless either. Underweight dogs may not be getting enough nutrition or there could be underlying health issues at play. Knowing the signs and acting early helps your pup stay happy, healthy, and full of energy.

How to tell if your dog is underweight

Veterinarians use a Body Condition Score (BCS) to assess dogs. On the 1–9 scale:

  • 1-3 = emaciated
  • 4–5 = ideal weight
  • 9 = obese

A healthy dog (BCS 4–5) typically has:

  • Ribs: easily felt but not visible from a distance
  • Waist: clearly visible from above
  • Abdominal tuck: belly slopes upward from chest to hips

⚠️ Pro tip: Breed and coat matter! Greyhounds naturally look slimmer, while fluffy dogs may require a hands-on check to feel their ribs and waist.

Signs your dog might be underweight

Your dog may be underweight if you notice:

  • Ribs clearly visible or easily felt under minimal fat
  • Waist easily seen from above
  • Abdominal tuck prominent
  • Minimal body fat
  • Hip bones and spine pronounced
  • Small, thin muscles

On the 1–9 scale, underweight dogs are typically BCS 1–3:

  1. Extremely thin, ribs and bones clearly visible, very little muscle
  2. Ribs obvious, minimal fat, mild muscle loss
  3. Ribs can be felt easily, waist visible, abdominal tuck present, minimal fat

Why dogs become underweight

Sometimes it’s simple: your dog isn’t getting enough calories. Other times, the cause is more complex. Common reasons include:

Not enough intake

  • Refusing food (loss of appetite)
  • Difficulty eating due to dental or mouth issues
  • Low-quality or insufficient food
  • Vomiting

Health issues affecting absorption or nutrition

  • Diabetes mellitus
  • Parasites in the gut
  • Kidney, liver, or intestinal disease
  • Exocrine pancreatic insufficiency
  • Tumors or cancer
  • Heart disease
  • Chronic fever, pregnancy, or high activity levels
  • Malabsorption or maldigestion

How to help your underweight dog

Every dog’s needs depend on size, breed, age, activity level, and neuter status. Feeding should match their individual requirements.
If your dog has lost weight without lifestyle or diet changes, or shows other concerning signs, it’s important to check with a vet.

During a consultation, a vet may review:

  • Appetite and daily calorie intake
  • Exercise levels
  • Environment and lifestyle
  • Other symptoms

They may recommend tests to rule out underlying medical conditions. Treatment depends on the root cause and can include dietary adjustments, supplements, or medical care.

Virtual veterinary consultations only available in BC and ON. Consultations are $95 plus tax. If medication is prescribed as a result of the consultation, you will be charged a service fee of $30 plus tax, regardless of the number of medications prescribed as a result of this consultation. Must be age of majority in your province. Any payments for consultations must be paid using a valid credit card. Other restrictions also apply. Visit telus.com/mypet for more information.

When to contact a vet

If your dog has lost weight unexpectedly, or doesn’t seem well in any way, it’s best to book a veterinary consultation. Virtual vet consultations are available in BC and ON through the TELUS Health MyPet app. Early intervention helps your dog regain a healthy weight, maintain muscle, and stay full of life.

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