Obesity is now the most common nutritional disease in dogs.

And the phenomenon continues to grow.

A large-scale American study conducted on nearly 4.9 million dogs between 2020 and 2023 showed that about one in two adult dogs (50.1%) is overweight or obese. Even more worrying, nearly a quarter of young adults are already overweight, which tends to persist with age.

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

The hardest part is often recognizing it.

According to the APOP 2022 report, more than a third of overweight or obese dog owners nevertheless think 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.

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

Why overweight damages the 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 exerted on the hips, elbows, knees and spine.

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

A study conducted on 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

Fatty tissue is not only used to store energy.

It also produces inflammatory molecules called adipokines, which maintain low-grade chronic inflammation. In a dog with osteoarthritis, this inflammation can contribute to increased pain and accelerated joint degradation.

Losing weight really improves osteoarthritis

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

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

In some dogs, this improvement is evidenced by gait analysis, and not just by the owners' impression.

How to know if your dog is overweight?

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

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

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

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

In case of doubt, a veterinarian can confirm the assessment and calculate your dog's target weight.

How to help a dog lose weight?

Weight loss is based on a few simple principles:

• gradually reduce calorie intake;
• maintain a sufficient protein intake;
• weigh the dog regularly;
• reevaluate the ration as the dog loses weight;
• maintain physical activity adapted to its health condition.

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

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

What to remember

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

This excess fat is not just a matter of aesthetics: it increases the stress on the joints, maintains chronic inflammation and promotes the development or worsening of osteoarthritis.

The good news is that weight loss, even moderate, 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 monitored 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.