What is obesity in pets?
Updated By PetymFacts checked against official sources on
Quick answer
Obesity in pets means carrying so much body fat that it harms health. Vets judge it with a body condition score, felt over the ribs, waist and belly, on a 9-point scale where 4 to 5 is ideal. Overweight dogs live shorter lives, and extra weight worsens arthritis, diabetes and breathing problems in flat-faced breeds.
Also called overweight dog, fat cat, pet obesity, canine obesity, feline obesity.
Key facts
- Body condition is scored on a 9-point scale: 4 to 5 is ideal, below 4 underweight and above 5 overweight. WSAVA
- In a study of over 50,000 neutered pet dogs across 12 breeds, overweight dogs had a shorter median life span in every breed, by up to about two and a half years. Journal of Veterinary Internal Medicine (2019)study
- Labradors fed 25% less than their pair-mates from puppyhood lived longer and developed signs of chronic disease later. Journal of the American Veterinary Medical Association (2002)study
- Obesity is the most common nutrition-related problem in cats. Cornell Feline Health Center
- In pugs and bulldogs a higher body condition score raised the risk of BOAS, the breathing disorder of flat-faced dogs. PLOS ONE (2017)study
- Obesity prevalence in pets is increasing in many parts of the world. WSAVA Global Nutrition Committee
How do you know if a pet is overweight?
Use your hands, not the scale alone. At an ideal weight you can feel the ribs easily under a thin layer of fat, see a waist from above and see a tuck behind the ribs from the side.
Weight alone misleads because breeds and individuals differ, which is why vets use body condition scoring. Run your flat palms along the chest: if you have to press to find the ribs, the pet is carrying extra fat. Look down from above for a waist behind the ribs, and from the side for the belly tucking up. A dog or cat with no waist, a sagging belly or fat over the base of the tail is overweight. Your vet can teach you to score your own pet.
In many Indian homes the extra calories come from love: rotis, biscuits and leftovers from several family members, plus a full bowl left out all day. Free feeding suits only pets that hold an ideal body condition on their own, and should not be used for pets prone to weight gain. If a pet gains weight on a modest diet, ask your vet to check for an underlying problem such as an underactive thyroid.
What does extra weight do to a pet's health?
| What the evidence shows | |
|---|---|
| Life span Journal of Veterinary Internal Medicine (2019)study | Overweight dogs had a higher risk of death at every age studied, and shorter median lives in all 12 breeds. |
| Joints Scientific Reports (2018)study | Heavier dogs had higher odds of an osteoarthritis diagnosis. |
| Diabetes Cornell University College of Veterinary Medicine | Obesity is one of the main risks for diabetes in cats. |
| Breathing PLOS ONE (2015)study | Obesity further raises the risk of BOAS in flat-faced dogs, and worsens its signs. |
| Heat Scientific Reports (2020)study | Dogs heavier than the average for their breed and sex were at higher risk of heat-related illness. |
How do you help a pet lose weight safely?
Slowly, and with a plan from your vet. Crash diets are dangerous, especially for cats.
- Ask your vet to score the pet, set a target weight and a daily calorie amount, and plan a safe rate of loss. Merck Veterinary Manual
- Weigh food with a kitchen scale and feed set meals instead of leaving a bowl out all day. WSAVA
- Keep treats and table food within about 10% of the day's calories, and tell every family member the rule. WSAVA
- Swap biscuits for low-calorie treats such as carrot, apple, melon or watermelon. WSAVA
- Ease hunger with several small meals, food puzzle toys and more play or walks in the cooler hours. WSAVA
- Weigh the pet every two weeks and adjust portions with your vet; a lower-calorie weight-management food can help. Merck Veterinary Manual
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Questions owners ask
How do I know if my dog is fat?
- Feel the ribs: at a healthy weight you can feel them easily without pressing, see a waist from above and a tummy tuck from the side. If you cannot feel the ribs, or there is no waist, your dog is probably overweight. Ask your vet to give a body condition score on the 9-point scale.
Does being overweight shorten a dog's life?
- Yes. A large study of over 50,000 neutered pet dogs found overweight dogs had shorter median life spans in all 12 breeds studied, by up to about two and a half years in Yorkshire Terriers. A lifelong study in Labradors found that lean-fed dogs lived longer and developed chronic disease later.
How fast should an overweight cat lose weight?
- Slowly, under a vet's supervision. Cornell's Feline Health Center advises slow, supervised weight loss. An overweight cat that stops eating or is food-deprived is at risk of hepatic lipidosis, a serious liver disease, so never starve a cat or cut its food sharply without your vet's plan.
Are neutered pets more likely to get fat?
- Neutered pets usually need fewer calories. Vets' starting estimates for daily energy are lower for neutered dogs and cats than for intact ones. Neutering does not have to mean weight gain: measure food, weigh the pet regularly and adjust portions after the operation, with your vet's guidance.
Keep reading
Related terms
More in health conditions
- ArthritisArthritis, or osteoarthritis, is a long-term joint disease in which worn cartilage lets the joint surfaces rub, causing stiffness, swelling and pain. It is very common in older dogs and cats. It cannot be cured, but pain relief from a vet, a healthy weight, gentle regular exercise and a few home changes keep most pets comfortable for years.
- Bloat (GDV)Bloat, or gastric dilatation-volvulus (GDV), is when a dog's stomach fills with gas and twists on itself, cutting off its blood supply. It mainly affects large and giant deep-chested breeds. Unproductive retching, a swelling belly, drooling and restlessness are the signs. It is a surgical emergency that can kill within hours.
- BOASBOAS, brachycephalic obstructive airway syndrome, is a breathing disorder of flat-faced dogs. Narrow nostrils, an overlong soft palate and a small windpipe block airflow, so affected dogs snore, snort, tire quickly and overheat easily. It is worse in heat, humidity and obesity. Surgery can widen the airway, and a lean weight helps.
- Canine distemperCanine distemper is a serious viral disease of dogs that can attack the skin, airways, gut and nervous system. It spreads in droplets from coughing, sneezing and barking, and through body fluids. There is no specific cure, and some dogs do not survive even with treatment. The D in the DHPPi vaccine prevents it.
- Canine parvovirusCanine parvovirus, or parvo, is a highly contagious virus that attacks a dog's gut and immune system. It spreads through infected faeces, survives a long time in the environment and hits unvaccinated puppies between 6 weeks and 6 months hardest. Vomiting and bloody diarrhoea can kill within days, and it is prevented by the core vaccine.
- Cat fluCat flu is the everyday name for an upper respiratory infection in cats. More than 90% of cases are caused by feline herpesvirus, feline calicivirus or both. Cats sneeze, have runny eyes and nose and may stop eating. Most recovered cats remain carriers, and stress can bring the virus back. Vaccination usually prevents severe disease.
- Cherry eyeCherry eye is when the tear gland inside a dog's third eyelid slips out of place and shows as a smooth, red, cherry-like lump in the inner corner of the eye. It is common in young Bulldogs, Beagles, Shih Tzus and Pugs, and needs a vet, usually for surgery to put the gland back.
- Chronic kidney diseaseChronic kidney disease (CKD) is a slow, lasting loss of kidney function, common in older cats and also seen in older dogs. Early on there are often no signs; later a pet drinks and urinates more, eats less and loses weight. It cannot be cured, but a kidney diet, water and regular checks can slow it.
- DehydrationDehydration means a pet's body has lost more water than it has taken in, through heat, panting, vomiting, diarrhoea or illness. Early on the gums turn sticky; then the skin loses its spring and the eyes sink. A mildly dehydrated pet needs water and a watchful eye; a weak, vomiting or collapsing one needs a vet now.
- Dental diseaseDental disease in pets is mostly periodontal disease: plaque bacteria inflame the gums (gingivitis) and then destroy the tissue and bone holding the teeth (periodontitis). It is the most common disorder vets diagnose in dogs, and very common in cats. Bad breath, tartar and red gums are the early signs. Daily brushing prevents most of it.
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Sources
Each source was opened and read on the date shown. How Petym checks its sources
- WSAVA: Frequently asked questions and myths (Global Nutrition Committee) (opens in a new tab)
- Cornell Feline Health Center: Feeding your cat (updated 30 April 2026) (opens in a new tab)
- WSAVA Global Nutrition Committee: Guidelines on selecting pet foods (updated 10 March 2021) (opens in a new tab)
- Cornell University College of Veterinary Medicine: Feline diabetes (Cornell Feline Health Center) (opens in a new tab)
- Merck Veterinary Manual: Nutritional requirements of small animals (full review November 2023, updated September 2024) (opens in a new tab)
- Merck Veterinary Manual: Feline hepatic lipidosis (opens in a new tab)
Show all 13 sourcesShow fewer
- Merck Veterinary Manual: Table: daily maintenance energy requirements for dogs and cats (opens in a new tab)
- Journal of Veterinary Internal Medicine (2019): Association between life span and body condition in neutered client-owned dogs, Salt and others (opens in a new tab)
- Journal of the American Veterinary Medical Association (2002): Effects of diet restriction on life span and age-related changes in dogs, Kealy and others (abstract read) (opens in a new tab)
- PLOS ONE (2017): Conformational risk factors of BOAS in pugs, French bulldogs and bulldogs, Liu and others (opens in a new tab)
- Scientific Reports (2018): Prevalence, duration and risk factors for appendicular osteoarthritis in a UK dog population under primary veterinary care, Anderson and others (opens in a new tab)
- PLOS ONE (2015): Impact of facial conformation on canine health: brachycephalic obstructive airway syndrome, Packer and others (opens in a new tab)
- Scientific Reports (2020): Incidence and risk factors for heat-related illness in UK dogs (opens in a new tab)