To help your dog lose weight, start with a vet visit to set a target weight and rule out medical causes. Then measure every meal, keep treats to about 10% of daily calories, and add daily low-impact exercise like walking or swimming. Slow, steady progress is safest: about 1% to 2% of your dog's body weight per week.¹
Is My Dog Overweight?
Extra weight is very common. In the Association for Pet Obesity Prevention's 2022 survey, 59% of dogs assessed at U.S. vet clinics were overweight or obese. Among pet parents whose pets scored in those ranges, 32% described their pet as normal, ideal, or even thin.²
Vets use a body condition score from 1 to 9, with 4 or 5 being ideal. At a healthy weight, you can feel your dog's ribs but not see them, and your dog has a tucked waist from above and a tucked belly from the side.¹ Try this quick check at home:
Check | Healthy weight | Likely overweight |
|---|---|---|
Ribs | Easy to feel with light pressure, but not visible | Hard to feel under a layer of fat |
Waist (from above) | A clear inward curve behind the ribs | Straight or wider at the middle |
Belly (from the side) | Tucks up toward the back legs | Level or sagging |
This check is a starting point, not a diagnosis. Your vet can give your dog an exact score and target weight.
Why Is My Dog Gaining Weight?
Most weight gain comes from more calories in than out. Common causes include:
Generous portions. Eyeballing food or using heaping scoops adds up quickly.
Too many treats and table scraps. Small snacks count, especially for small dogs.
Less activity. Senior dogs and busy households often get fewer long walks.
Medical causes. According to Cornell University's College of Veterinary Medicine, conditions like hypothyroidism and Cushing's disease, genetics, and certain medications can also play a role.¹
That's why a vet visit comes first. Bring a list of questions to ask your vet, including your dog's ideal weight and how many calories they need each day.
How Fast Should a Dog Lose Weight?
Slow and steady is the goal. Cornell's vets say dogs can safely lose about 1% to 2% of their body weight each week. Losing weight faster may mean calories are cut too much or signal a health problem.¹
Here's what that looks like for dogs of different sizes:
Dog's current weight | Safe weekly loss (1% to 2%) |
|---|---|
20 pounds | About 0.2 to 0.4 pounds |
50 pounds | About 0.5 to 1 pound |
80 pounds | About 0.8 to 1.6 pounds |
It can feel slow, but small weekly losses are easier to keep off and safer for your dog.
How Much Should I Feed My Dog to Lose Weight?
Ask your vet to calculate a daily calorie target based on your dog's ideal weight, not their current weight. Then measure every meal with a measuring cup or, better yet, a kitchen scale. Heaping portions can add extra calories and sabotage your plan.¹
A few habits help:
Split the daily amount into two or more meals.
Use a slow feeder or puzzle toy so meals last longer.
Make sure everyone in the house knows the plan.
To understand where your dog's calorie target comes from, read our guide on how many calories your dog needs.
How Many Treats Can a Dog Have on a Diet?
Treats should make up only about 10% of your dog's daily calories.¹ You don't have to cut them out entirely. Try these swaps:
Use their kibble. Set aside a few pieces from your dog's daily portion to use as treats.
Go small. Break treats into tiny pieces. Your dog cares more about the reward than the size.
Try veggies. Green beans and carrot slices are crunchy, low-calorie options. Check our list of dog-safe vegetables before you share.
Reward with attention. Praise, play, and belly rubs count too.
What Exercise Helps a Dog Lose Weight?
Exercise helps, but it works best alongside diet changes. Cornell notes that physical activity alone usually won't make enough difference, and suggests low-impact options like walking or swimming.¹
Start slowly, especially if your dog is very overweight or older. Add a few minutes to each walk every week, and watch for heavy panting or limping. Swimming is easy on the joints, so it's a great option for heavier dogs. Our dog swimming guide explains how to get started safely.
How Do You Keep the Weight Off?
Weigh your dog every few weeks, either at home or at your vet's office, and write it down. If progress stalls for more than a few weeks, check portions and hidden snacks first, then ask your vet about adjusting the plan.
Once your dog reaches their goal, your vet may adjust their daily calories for maintenance. Keep measuring meals and counting treats so the weight doesn't creep back. Staying at a healthy weight matters, since Cornell notes that obesity affects nearly every major organ and often leads to shorter lifespans.¹
Frequently Asked Questions
How long does it take for a dog to lose weight?
It depends on how much your dog needs to lose. At a safe pace of about 1% to 2% of body weight per week, a dog that's 10% over their ideal weight might reach their goal in roughly five to 10 weeks.¹ Dogs with more to lose will take longer. Your vet can help you set realistic milestones.
Can exercise alone help my dog lose weight?
Usually not. Exercise burns calories and supports joint and heart health, but it rarely makes enough difference without diet changes. The most effective plans combine measured meals, fewer treats, and daily low-impact activity like walking or swimming. Ask your vet how much exercise is right for your dog's age and health.
Why isn't my dog losing weight?
Hidden calories are the most common reason. Check for extra treats, table scraps, and portions that aren't measured, and make sure everyone in your home follows the same plan. If your dog still isn't losing weight after a few weeks, see your vet, since medical conditions like hypothyroidism can make weight loss harder.
Is it safe to put my dog on a diet without seeing a vet?
It's best to talk to your vet first. Cutting food too much can deprive your dog of nutrients, and losing weight too fast can be a sign of a health problem. Your vet can rule out medical causes, set a target weight, and advise how much to feed so your dog loses weight safely.
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Cornell University College of Veterinary Medicine, Riney Canine Health Center. "Obesity and Weight Loss in Dogs." Cornell CVM, updated June 2024. https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-topics/obesity-and-weight-loss-dogs
Association for Pet Obesity Prevention. "World Pet Obesity Month Puts Pets First With New Communication Guidelines." APOP, September 27, 2026. https://www.petobesityprevention.org/articlesandnews/2k8a1vopmvk2wai75e3w6zfit5bemc
