TL;DR
Obesity in dogs is extra body fat that shortens life and loads the joints, heart and metabolism, and it is one of the most common problems vets see. In a UK study of 22,333 dogs, 7.1% were diagnosed as obese in a single year, the third most common diagnosis of all, and many more are overweight without a diagnosis. Being overweight in middle age cut median lifespan in all 12 breeds studied across 50,787 dogs: overweight Yorkshire Terriers lived 13.7 years against 16.2 for lean ones. In a lifelong study of 48 Labradors, dogs fed 25% less than their littermates lived significantly longer and developed chronic disease later. The fix works: in an international study of 926 overweight dogs on a weight-loss diet, 97% lost weight in three months, an average of 11.4% of body weight, and owners reported more activity and better quality of life. Our founder Morty's own corgi is on a diet right now, so this one is personal.
Is my dog overweight?
Vets use a body condition score (BCS) from 1 to 9, where 4 to 5 is ideal. You can check at home in a minute:
| Check | Ideal (BCS 4 to 5) | Overweight (BCS 6 to 7) | Obese (BCS 8 to 9) |
|---|---|---|---|
| Ribs | Easy to feel with a thin fat cover, like the back of your hand | Felt with some pressure | Hard or impossible to feel |
| Waist from above | Clear waist behind the ribs | Waist hard to see | No waist; back is broad and flat |
| Belly from the side | Tucked up | Little tuck | Belly hangs; fat over the base of the tail |
Weigh your dog every 2 to 4 weeks on the same scale and write it down. Small changes are easier to fix early.
Why weight matters so much
A shorter life
In a study of 50,787 middle-aged neutered pet dogs in North America, overweight dogs had a higher risk of death throughout life in every one of 12 breeds:
| Breed | Lean median lifespan | Overweight median lifespan |
|---|---|---|
| Yorkshire Terrier | 16.2 years | 13.7 years |
| German Shepherd | 12.5 years | 12.1 years |
The risk of death was 1.35 to 2.86 times higher in overweight dogs, depending on breed. The study authors recommend keeping dogs lean particularly from midlife onward. See Yorkshire Terrier lifespan and German Shepherd lifespan.
The famous Labrador study
Forty-eight Labradors were paired at 8 weeks old, and one dog in each pair was fed 25% less than its pair-mate for life. The leaner dogs:
- Had lower body fat, insulin and blood sugar.
- Lived significantly longer.
- Developed signs of chronic disease later.
In the same dogs, better insulin sensitivity was linked to a lower risk of dying or needing treatment for chronic disease, and to a later start of arthritis treatment. See Labrador lifespan.
Joints, back, heart and more
Extra weight increases the load on every joint, raises the risk of diabetes, bladder stones and Cushing's disease, and makes heart disease and breathing problems in flat-faced breeds harder to live with.
Our founder's corgi
Morty's current dog is a 6-year-old corgi. It is sweet, clingy and clever, and it is always hungry. It is on the heavy side right now, so it is on a controlled diet. Corgis also need plenty of exercise: when Morty's corgi has not had enough, it has wrecked a mattress, a sofa and shoes.
Weight is a bigger deal for corgis than for many breeds. A small-animal vet Morty has known for years, who asked us not to use their name, puts it simply: "Corgis put on weight easily, and their short legs already put extra load on the spine." Long-backed breeds such as corgis and Dachshunds are prone to back and hip problems, and every extra kilo adds strain. See Corgi lifespan and Dachshund lifespan.
Morty's corgi has had no joint problems so far, and Morty gives it our New Zealand Green-Lipped Mussel Powder as part of a prevention routine, alongside keeping its weight down. That is one owner's experience, not a promise, but weight control is the part every corgi owner can start today.
How to help your dog lose weight
1. Get a target and a calorie number
Ask your vet for a target weight and a daily calorie allowance. In the international study, weight-loss diets were started at a calculated energy allowance based on the target weight, and nearly every dog lost weight on that plan.
2. Measure every meal
- Weigh food on a kitchen scale. Scoops and cups are inaccurate.
- Use a weight-loss diet if more than a little weight needs to come off. These are designed to keep protein, vitamins and minerals complete while calories drop. In a referral clinic study of 143 obese dogs, feeding a dry weight-management diet was linked to success. See senior dog food for weight loss.
- Count treats. Many vets suggest keeping treats to about 10% of daily calories. Use part of the daily kibble as treats, or vegetables such as green beans or carrot.
- One person feeds, or keep a written log, so the dog does not get fed twice.
3. Add activity
Start with longer, steady walks and build up. Swimming and walking on soft ground are kind to joints. For older dogs, see senior dog exercise.
4. Weigh in and adjust
Weigh every 2 to 4 weeks. If weight is not falling, cut the allowance further with your vet rather than giving up.
5. Expect it to take months
In the referral clinic study, 61% of obese dogs reached their target weight, while about a third stopped early, often because owners stopped following the plan. Faster, steady weight loss and staying on the program longer were both linked to success. Dogs that started with more body fat found it harder, which is why acting early matters.
Protect muscle in senior dogs
Older dogs lose muscle as well as fat. A weight-loss plan for a senior should keep protein high and include daily walking so the weight that comes off is fat. See high-protein senior dog food and muscle atrophy in dogs.
When weight gain is a medical problem
See a vet if your dog gains weight without eating more, or also has thin hair, lethargy, cold intolerance, increased thirst or a pot belly. An underactive thyroid or Cushing's disease can cause weight gain, and a swollen belly can be fluid, not fat.
FAQ
How do I know if my dog is obese?
If you cannot easily feel the ribs, cannot see a waist from above and the belly does not tuck up, your dog is likely overweight. A body condition score of 8 to 9 out of 9 is obese.
Does obesity shorten a dog's life?
Yes. In a study of over 50,000 dogs, overweight dogs had shorter median lifespans in all 12 breeds studied, by up to 2.5 years in Yorkshire Terriers.
How fast should a dog lose weight?
Gradually, under a vet's plan. In an international study, dogs lost an average of 11.4% of body weight over three months on a weight-loss diet.
What is the best way to help a dog lose weight?
Set a target weight with your vet, weigh every meal, use a weight-loss diet, count treats and increase activity gradually, then weigh in every few weeks.
Which dog breeds become overweight easily?
Labradors and corgis are the breeds our vet friend sees most often for weight problems, but any dog that is overfed and underexercised will gain weight.
References
- O'Neill DG, et al. Prevalence of commonly diagnosed disorders in UK dogs under primary veterinary care: results and applications. BMC Veterinary Research. 2021. PMID: 33593363
- Salt C, et al. Association between life span and body condition in neutered client-owned dogs. Journal of Veterinary Internal Medicine. 2019. PMID: 30548336
- Kealy RD, et al. Effects of diet restriction on life span and age-related changes in dogs. Journal of the American Veterinary Medical Association. 2002. PMID: 11991408
- Larson BT, et al. Improved glucose tolerance with lifetime diet restriction favorably affects disease and survival in dogs. Journal of Nutrition. 2003. PMID: 12949383
- Flanagan J, et al. Success of a weight loss plan for overweight dogs: the results of an international weight loss study. PLOS ONE. 2017. PMID: 28886096
- German AJ, et al. Cohort study of the success of controlled weight loss programs for obese dogs. Journal of Veterinary Internal Medicine. 2015. PMID: 26426704
For individual health questions, your veterinarian remains the best partner.
