The vet had both hands on his sides, pressing gently along his ribs, the way you feel for a light switch in the dark. Then she said it, in a voice meant to keep it small: he could stand to lose a few pounds.
On the drive home you went through his day. The crust of your toast in the morning. The biscuit for coming back inside. Whatever slid off the cutting board while you made dinner. None of it felt like overfeeding while it was happening.
If he also has sore joints, those few pounds matter more than they sound.
Quick answer
Does weight loss help a dog with arthritis? If he is overweight, the international arthritis guidelines make it part of his plan. In one small trial without a comparison group, lameness eased once the dogs had lost about 6 percent of their body weight. It is a plan your vet sets and paces, with his muscle checked as the weight comes off. Start by weighing what he eats in a day. If he is already at a good weight, the work is keeping him there.
Does losing weight help a dog with arthritis?
If he is overweight, yes, and it can take less than you might think. In a trial of 14 obese dogs with arthritis in the hips or elbows, lameness scores improved once the dogs had lost about 6 percent of their body weight (Marshall et al., 2010).
Force plates, which measure how much weight each leg is willing to carry, showed the change once the dogs had lost about 9 percent (Marshall et al., 2010). In that trial’s terms, on a 70-pound dog, 6 percent is a little over four pounds.
The international guidelines for arthritis in dogs start every dog’s plan at the scale: weigh him, judge that weight against his body condition, his muscle and his age, and aim to hold an ideal weight for life. For the dog who is carrying extra, they add a weight-management program as an early step (Cachon et al., 2023).
The weight-loss trials themselves are small: that one followed 14 dogs, and an earlier one followed 9 (Impellizeri et al., 2000). The larger trial also had no comparison group. Every dog in it was losing weight, so nothing in the study shows how much of the change came from the weight loss itself.
Why do a few pounds make that much difference?
Picture walking all day with a backpack you are not allowed to put down. For a dog with arthritis, the extra pounds are that backpack, and every step lands on joints that already hurt. The arthritis guidelines describe it in two parts: excess weight increases the load on the joints, and it has a metabolic contribution as well (Cachon et al., 2023).
The second part is less settled in dogs. A 2026 study took a single snapshot of blood markers in dogs with and without arthritis. Compared with healthy dogs, the obese dogs with arthritis differed mainly in metabolic markers such as cholesterol, rather than in the inflammatory markers the researchers measured (Agudelo-Giraldo et al., 2026). A single snapshot can show a difference, not what caused it.
Dogs that reach their target weight seem to gain more than an easier walk. A study of 50 obese dogs, not chosen for arthritis, had owners fill in a validated quality-of-life questionnaire before and after a weight-loss program. For the 30 dogs that reached their target, vitality scores went up and pain and emotional-disturbance scores went down. Anxiety scores didn’t change (German et al., 2012).
How can I tell if my dog is overweight?
Your vet judges it by hand and by eye, on a nine-point body condition score. The weight management guidelines from the American Animal Hospital Association (AAHA) use 5 out of 9 as the reference point for an ideal weight (AAHA, 2014).
Seeing him every day can make it harder to judge. The same guidelines cite one study in which 39% of owners whose dogs the vet had called overweight thought their dog’s weight was fine (AAHA, 2014). Part of it may be that the change arrives a few ounces at a time, and you are there for every one of them.
His muscle gets a score too. AAHA asks vets to record muscle condition next to body condition, so that the fat he loses and the muscle he loses can be tracked apart. In an older dog that second number deserves close watching, because muscle can thin out even when his weight on the scale hasn’t moved.
AAHA adds that senior pets may need closer monitoring of protein and muscle while they lose weight.
What does a safe weight-loss plan look like?
It is a plan you run with your vet, and it usually covers these pieces:
- A starting point. His weight, body condition score and muscle score, recorded on the same day.
- A target and a daily amount. Your vet sets the target weight, the food, and how much of it he eats to get there. Don’t start by cutting his bowl in half on your own.
- Food weighed, not scooped. AAHA’s guidelines suggest weighing dry food on a kitchen scale, because a measuring cup can be imprecise.
- Treats counted in. The toast crust and the biscuit belong inside his daily amount, not added on top (AAHA, 2014).
- Regular weigh-ins. At the clinic, or at home if your vet is happy with that.
- A watch on his muscle. If his muscle score drops, AAHA tells vets to check his protein and whether the weight is coming off too fast or something else is going on.
Movement belongs in the same plan. A small trial of 29 dogs, all on the same diet, compared a home-based physical therapy program with an intensive one; the intensive group lost more weight and moved better (Mlacnik et al., 2006). How much exercise a sore dog can take is its own question.
Weight loss takes time, and he may still be sore along the way. Ask your vet what he can take for it. Don’t give him ibuprofen, acetaminophen or any other human painkiller: they can poison a dog, even in amounts that seem modest.
Why is the weight so hard to keep off?
Reaching the target is the first stretch. In that quality-of-life study, 30 of the 50 dogs got there (German et al., 2012).
A follow-up study by the same group tracked 33 dogs that had successfully lost weight, for a median of about 21 months. Fourteen held their new weight, and three lost more than 5 percent beyond it. Sixteen, close to half, gained back more than 5 percent (German et al., 2012).
The dogs that stayed on a food made for weight loss regained less than the dogs switched back to a standard maintenance food. Which food fits your dog after the target is a question for your vet.
So treat the target weight as a halfway point. When he gets there, ask what his new daily amount is, and keep weighing him.
What if he’s already lean?
Then the goal is to hold that weight. The arthritis guidelines ask for an optimal weight kept over a dog’s lifetime, so a dog already at his ideal weight doesn’t need a diet (Cachon et al., 2023).
The longest data on why it matters comes from 48 Labrador Retrievers followed from puppyhood, half of them fed 25 percent less than the dog they were paired with. By age 14, 20 of the 24 dogs fed more showed x-ray signs of hip arthritis, against 12 of the 24 lean dogs (Smith et al., 2006).
Those dogs were kept lean from the start, so it shows the value of a lifetime of leanness; it says nothing about a diet started late.
Large-breed puppies need a different plan for their growing joints.
Where do I start?
Before his next appointment, put a kitchen scale next to his bowl and weigh one ordinary day of what he eats, treats included. That number is where the plan starts.
Next time your vet runs her hands along his sides, you’ll know what she is scoring.
Common questions
How fast should my dog lose weight?
Slowly. The AAHA weight management guidelines give vets a target rate for dogs of 1 to 2 percent of body weight a week. Your vet decides where he fits in that range and checks it at each weigh-in. Loss may be slower in a dog with certain other health conditions. What you can watch at home is his muscle: if his back starts to feel thinner while he slims down, call your vet.
Will losing weight cure his arthritis?
No. Osteoarthritis is a progressive joint disease, and the international guidelines manage it in layers: a base nearly every dog gets, including a healthy weight, and more added as it advances (our guide to arthritis without a limp walks through them). For a dog carrying extra, a weight-loss program is one of the first things added, with pain relief brought in as his signs call for it. What the lameness trials in this article measured was how the dogs walked, and that eased as the pounds came off.
Can I just feed him less of his usual food?
Only with your vet’s say-so. Dog foods balance their nutrients to their calories, so a smaller portion of his usual food also means less of every essential nutrient. The AAHA guidelines prefer a therapeutic weight-loss food, available only through your vet or with their prescription, over smaller portions of an over-the-counter food, because it is more likely to keep his nutrient intake adequate on fewer calories. Those foods carry more protein, vitamins and minerals per calorie, and high protein may preserve muscle during weight loss.
Sources
- AAHA (Brooks D, et al.). 2014 AAHA Weight Management Guidelines for Dogs and Cats. Journal of the American Animal Hospital Association. 2014;50(1):1-11. Link
- Agudelo-Giraldo L, López C, Carmona JU. Phenotypic Differences in Inflammatory, Metabolic, and Biochemical Biomarkers in Dogs with Osteoarthritis According to Body Condition and Sex. Animals. 2026;16(4):692. Link
- Cachon T, et al. COAST Development Group’s international consensus guidelines for the treatment of canine osteoarthritis. Frontiers in Veterinary Science. 2023;10:1137888. Link
- German AJ, et al. Quality of life is reduced in obese dogs but improves after successful weight loss. The Veterinary Journal. 2012;192(3):428-434. Link
- German AJ, Holden SL, Morris PJ, Biourge V. Long-term follow-up after weight management in obese dogs: the role of diet in preventing regain. The Veterinary Journal. 2012;192(1):65-70. Link
- Heseltine J. Hypothyroidism in Animals. Merck Veterinary Manual, reviewed May 2024. Link
- Impellizeri JA, et al. Effect of weight reduction on clinical signs of lameness in dogs with hip osteoarthritis. JAVMA. 2000;216(7):1089-1091. Link
- Koehler R. Is Your Dog Losing Weight? Common Causes and When It’s Time for a Vet Visit. PetMD. Nov. 11, 2025. Link
- Marshall WG, Hazewinkel HAW, Mullen D, et al. The effect of weight loss on lameness in obese dogs with osteoarthritis. Veterinary Research Communications. 2010;34(3):241-253. Link
- Mlacnik E, Bockstahler BA, Müller M, et al. Effects of caloric restriction and a moderate or intense physiotherapy program for treatment of lameness in overweight dogs with osteoarthritis. JAVMA. 2006;229(11):1756-1760. Link
- Smith GK, et al. Lifelong diet restriction and radiographic evidence of osteoarthritis of the hip joint in dogs. JAVMA. 2006;229(5):690-693. Link