How Many Calories Should My Dog Eat to Lose Weight?
A common vet starting point for weight loss is to feed your dog its resting energy requirement (RER) at its target weight, not its current weight. That is 70 × (target weight in kg) to the power 0.75, in calories a day, a guideline from the AAHA 2021 Nutrition and Weight Management Guidelines. From there, your vet adjusts the amount based on regular weigh-ins.
Our dog calorie calculator does the maths: choose “Weight loss”, enter the current and target weights, and it gives the daily calories and the treat allowance. Treat the result as a starting estimate. Check with your vet before starting a diet, so they can set the target weight and rule out a medical cause for the weight gain.
Why calories are counted at the target weight
A dog’s calorie needs are worked out from its weight. If you base them on the current, heavier weight, you feed for the extra pounds and the dog stays where it is. Basing them on the ideal weight means the dog eats less than it burns, and the body uses its fat stores to make up the gap.
Feeding for the target weight is also safer than simply cutting the bowl in half. A planned calorie number lets you keep the diet balanced and the weight loss steady.
The formula, step by step
These are the formulas our calculator uses:
- Convert the target weight to kilograms: kg = lb × 0.4536.
- Resting energy (RER) = 70 × (target weight in kg) to the power 0.75 calories per day. Raising weight to the power 0.75 reflects that bigger dogs need fewer calories per pound than small dogs (NRC 2006).
- Weight-loss calories = 1.0 × RER at the target weight (AAHA 2021).
- Treats = no more than 10% of that daily total (WSAVA).
If your vet gives you a different energy factor, choose “Custom factor” in the calculator and enter it.
How it compares with normal feeding
For context, the calculator’s maintenance factors for adult dogs are 1.6 × RER for a spayed or neutered adult, 1.8 × RER for an intact adult and 1.4 × RER for an inactive dog or one that gains weight easily (Merck Veterinary Manual). Weight loss at 1.0 × RER uses the ideal weight and the lowest factor, which is why it creates a calorie deficit.
How to find your dog’s target weight
You need a target before you can work out the calories. Your vet is the best person to set it, but you can get a first estimate from your dog’s body condition score.
The body condition score (BCS) runs from 1 to 9, with 5 as ideal: ribs easy to feel under a thin layer of fat, a visible waist from above and a tummy tuck from the side. Our dog ideal weight calculator uses the WSAVA body condition chart, where each point above 5 is roughly 10% over the ideal weight, to estimate the target.
A safe pace
Slow and steady is the goal. The AAHA weight management guidelines give a safe loss for dogs of 1% to 2% of body weight per week. The ideal weight calculator shows how many pounds a week that is for your dog and roughly how many weeks it will take.
Losing faster than that is not better. It is harder to stick to, more likely to leave your dog hungry, and more likely to rebound.
Turning calories into food
A calorie target only helps once it is turned into an amount of your own food:
- Find the calorie statement on the bag or can (US labels must list kcal per kg and per cup or can).
- Divide the daily calories, minus any treat calories, by the kcal per cup to get cups a day.
- Split that into two or more meals.
- Measure with a standard 8 fl oz measuring cup filled level, or better still weigh it on a kitchen scale.
The dog food calculator does this from your label, and our guide to how many cups of dog food per day explains the label numbers in more detail. If your dog is on a vet weight-loss diet, use that food’s own calorie numbers.
Tips that make weight loss work
- Weigh your dog regularly. Use the same scale each time, such as every two weeks, and write it down.
- Count every treat and chew. Dental chews, table scraps and training treats all add up. Keep them within the 10% allowance.
- Use low-calorie treats. Many dogs are just as happy with small pieces of their own kibble from the day’s amount.
- Measure every meal. Eyeballing a scoop is one of the main reasons diets stall.
- Add activity. Extra walks and play help, but ask your vet how much exercise suits your dog, especially if it is very overweight or has joint problems.
- Get the whole household on board. One person handing out extra snacks can undo the plan.
- Keep fresh water available at all times.
When to see the vet
Book a check-up before starting, and go back if your dog:
- is not losing weight after several weeks on the plan
- is losing weight faster than the safe pace
- seems very hungry, tired or unwell
- has a medical condition or takes medication
Some medical problems, such as an underactive thyroid, can cause weight gain, and your vet can test for these.
Frequently asked questions
How many calories should my dog eat to lose weight?
A common vet starting point is 1.0 × RER at the target weight, where RER = 70 × (target weight in kg) to the power 0.75. The dog calorie calculator works it out when you choose “Weight loss”. Your vet then adjusts the amount based on how your dog is doing at weigh-ins.
How fast should a dog lose weight?
The AAHA guidelines give 1% to 2% of body weight per week as a safe pace for dogs. The dog ideal weight calculator shows what that means in pounds for your dog and how many weeks it should take to reach the target.
Should I just feed my dog less of its normal food?
Cutting back a little can work, but a large cut to a normal food can leave your dog short of protein, vitamins and minerals. Work out a calorie target first and ask your vet whether your dog’s normal food is suitable or whether a weight-loss food would be better.
Do treats count toward my dog’s calories?
Yes. Keep treats and chews to no more than 10% of the day’s calories and take them out of the main meals. The calorie calculator shows that 10% allowance for your dog.
How do I know my dog’s ideal weight?
Ask your vet, who can assess your dog’s body condition score. As a first estimate, a score of 5 out of 9 is ideal, and each point above 5 is roughly 10% over the ideal weight, which is what the ideal weight calculator uses.