Overweight and obesity in dogs

What is overweight in dogs?

Overweight occurs when energy intake is structurally higher than energy expenditure. Veterinary surgeons assess this using the Body Condition Score (BCS), a scale from 1 to 9 where 4–5/9 is considered ideal. A BCS of 6 or higher indicates overweight; from 7–8 onwards, this is referred to as obesity. The BCS correlates reliably with actual body fat percentage and is therefore the practical standard method [3].

How big is the problem?

In the US, 44–50% of adult dogs are overweight or obese [1]. The risk peaks in the mature age group, with percentages of over 50% overweight and nearly 13% obese. Dogs that were already overweight as puppies have 1.85 times more chance of remaining overweight as adults [3] — early intervention is therefore crucial.

Breeds with increased risk: Labrador Retriever, Cavalier King Charles Spaniel, Cocker Spaniel, Beagle and Basset Hound. Neutered dogs of both sexes also have a higher risk [3].

What are the consequences?

The consequences are well documented in multiple studies [1][3]:

• Shorter life expectancy — Labrador research shows up to approximately 1.8 years less lifespan
• Earlier and more severe osteoarthritis
• Reduced glucose tolerance (increased risk of diabetes)
• Increased anaesthetic risk
• Skin and urogenital disorders
• Greater chance of certain tumours

What is proven to work?

Caloric restriction and exercise

The only proven effective approach is a combination of caloric restriction (60–70% of calculated maintenance requirements) and structured exercise [3]. Prescription diets with a high protein content and more fibres demonstrably lead to successful weight loss more often than regular food (57.5% vs. 42.2%) [2].

Important caveat: only 43.5% of dogs in veterinary weight programmes actually reach a healthy weight [2]. The involvement and consistency of the owner appear to be the strongest predictors of success — not the diet itself.

Additional options: what does the evidence say?

Additional interventions can support the dog's motivation to move and quality of life, but are never a replacement for dietary adjustment under the supervision of a veterinary surgeon.

When to see a veterinary surgeon?

Consult a veterinary surgeon to objectively determine the BCS, rule out hormonal diseases (such as hypothyroidism or Cushing's syndrome), and draw up an individual nutrition and exercise plan. Always start with the veterinary surgeon before beginning a calorie-restricted diet — unguided restrictions can be harmful.