Obesity is currently the most frequent nutritional disease in dogs.

And the phenomenon continues to progress.

A large American study of nearly 4.9 million dogs between 2020 and 2023 showed that about one in two adult dogs (50.1%) are overweight or obese. Even more concerning, almost a quarter of young adults already have excess weight, which tends to persist with age.

France is not spared. A study conducted in the veterinary schools of Maisons-Alfort and Toulouse confirms that overweight has become a real health problem for French dogs.

The most difficult part often remains recognizing it.

According to the APOP 2022 report, more than a third of overweight or obese dog owners believe their pet is at its ideal weight.

Why do some dogs gain weight more easily?

Overweight does not depend solely on the amount of food.

Several factors increase the risk:

• age;
• sterilization;
• certain genetic predispositions;
• lack of physical activity;
• the eating habits of the whole family.

After sterilization, energy needs often decrease. Without adjusting the ration, weight gain becomes common.

Certain breeds are also more sensitive. In Labrador Retrievers, for example, a mutation in the POMC gene promotes a greater feeling of hunger and increases the risk of obesity.

Why excess weight damages joints

The link between obesity and osteoarthritis is now one of the best-demonstrated in veterinary medicine.

Two mechanisms explain this effect.

 

Mechanical overload

Each extra kilo increases the stress on the hips, elbows, knees, and spine.

In the long term, this overload accelerates cartilage wear and promotes the onset of osteoarthritis.

A study in Labradors showed that dogs receiving a more controlled diet developed radiographic signs of hip osteoarthritis about six years later than those fed more generously. A considerable difference achieved solely through weight management.

 

Chronic inflammation

Fat tissue does not only serve to store energy.

It also produces inflammatory molecules called adipokines, which maintain low-grade chronic inflammation. In an arthritic dog, this inflammation can contribute to increased pain and accelerate joint degradation.

Weight loss truly improves osteoarthritis

Weight loss is one of the most effective non-pharmacological measures against canine osteoarthritis.

Studies show that a reduction of about 6 to 10% of body weight is enough to significantly reduce lameness and improve locomotion.

In some dogs, this improvement is objectified by gait analyses, and not just by owner impression.

How to tell if your dog is overweight?

Veterinarians use the Body Condition Score (BCS), a body condition score typically evaluated on a 9-point scale.

A dog is considered to be at an ideal weight when:

• its ribs are easily palpable without being visible;
• its waist remains noticeable from above;
• its abdomen tucks up slightly when viewed from the side.

Conversely, if the ribs become difficult to feel and the waist disappears, overweight is probably already established.

If in doubt, a veterinarian can confirm the evaluation and calculate your dog's target weight.

How to help a dog lose weight?

Weight loss is based on a few simple principles:

• gradually decrease calorie intake;
• maintain sufficient protein intake;
• regularly weigh the dog;
• re-evaluate the ration as weight loss progresses;
• maintain physical activity appropriate to its health status.

Foods specially formulated for weight loss can be useful, but they do not replace a precise calculation of the ration.

Veterinary monitoring allows the program to be adapted and avoids deficiencies or too rapid weight loss.

Key takeaways

Nearly one in two adult dogs is now overweight or obese.

This excess fat is not just an aesthetic issue: it increases stress on the joints, maintains chronic inflammation, and promotes the onset or worsening of osteoarthritis.

The good news is that even moderate weight loss often improves mobility, reduces pain, and helps preserve the dog's quality of life.

 

 

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Sources 

1. Montoya JA et al. (2025). Epidemiological study on the prevalence of overweight and obesity in nearly 4.9 million dogs followed in primary care in the United States.
2. Blanchard G et al. (2024). French study on the prevalence of canine overweight and obesity in the veterinary schools of Maisons-Alfort and Toulouse.
3. Association for Pet Obesity Prevention (APOP). 2022 Pet Obesity Survey.
4. Marshall WG et al. (2010). The effect of weight loss on lameness in obese dogs with osteoarthritis.
5. Impellizeri JA et al. (2000). The effect of weight reduction on clinical signs of lameness in dogs with hip osteoarthritis.
6. Smith GK et al. (2006). Effects of lifelong diet restriction on the development of osteoarthritis in dogs.
7. Lund EM et al. (2016). Epidemiology of canine overweight and obesity.
8. Raffan E et al. (2016). A deletion in the canine POMC gene is associated with weight and appetite in Labrador Retrievers.
9. Simpson JW et al. (2019). Review of canine obesity and its metabolic and locomotor consequences.