What is a good weight-loss diet plan for a dog? One that is slow, steady, and simple: measured food, a little more exercise, a monthly weigh-in, and a target that is set with your vet. This guide is the full plan, week by week: how to start, how many calories to feed, how to build exercise up, how to handle plateaus, and how to keep the weight off once it is lost. Every figure is an estimate, and a dog that needs to lose a lot of weight should have a plan set with its vet — especially a cat, where rapid weight loss can cause a serious liver problem.
The short version is: weigh the dog, set a target weight with your vet, feed a measured amount of a complete and balanced food at about 1.1 times the resting energy requirement, keep treats under 10% of daily calories, and aim for about 1% of body weight per month. Weigh monthly, and if weight is not moving after a month, cut food by about 10% and re-weigh in another month. The how to help a dog lose weight safely guide gives the same plan in shorter form, and the best food for overweight dogs guide explains how a weight-loss food differs from a normal food.
Step 1: weigh and set a target
Weigh the dog — monthly, at the same time of day, on the same scales — and write the number down. Then set a target weight: a good target is usually 10 to 20% below the current weight to start with, not the ideal weight in one go. A 30 kg dog that should be 25 kg should aim for 27 to 28 kg first, and then for 25 kg once it gets there. A target that is too far away is discouraging, and a dog that has to lose a lot of weight needs to lose it in stages, with a new target set at each stage. Ask your vet to set the target, and to check the dog before the plan starts.
Work out the target weight loss per month: about 1% of body weight per month. A 30 kg dog losing 1% a month loses about 300 g a month, and will take about 15 months to lose 5 kg — which sounds slow, and it is, but slow weight loss is the kind that stays off. A 5 kg cat losing half a percent to 1% a month loses about 25 to 50 g a month. Write the target and the monthly rate down, and keep the record with the weigh-ins: the line over months is what matters, not any single reading. The dog ideal weight calculator works out a target weight range, and the how to weigh your dog at home guide explains the bathroom-scale method.
Step 2: work out the calories
Start with the resting energy requirement, or RER — the calories a dog burns at rest. The formula vets use is: RER equals 70 times body weight in kg to the power of 0.75. A dog that needs to lose weight usually needs about 1.1 times its RER as a starting point. The table below gives the daily calories for a dog at different weights, at the normal adult factor and at the weight-loss target. Use the row nearest the dog's current weight, and feed the target amount, measured with scales or a measuring cup.
| 5 kg | 375 | 255 | | 10 kg | 630 | 435 | | 20 kg | 1060 | 730 | | 30 kg | 1435 | 985 | | 40 kg | 1780 | 1225 |
If weight is not moving after a month, cut food by about 10% and re-weigh in another month. If weight is falling faster than about 1% of body weight per month, feed a little more. Note that calories are the real target and cups are only a translation: different foods have very different calorie densities, so always check the kcal per cup or per 100 g on your own bag or tin and work from that. The dog calorie calculator works out the same figures for any weight, and the how many calories to lose weight for dogs guide gives the full tables.
Step 3: choose the food and the routine
Feed a complete and balanced food made for weight loss, or feed less of the normal food with your vet's agreement. A weight-loss food carries fewer calories per mouthful — less fat, more fibre, and enough protein to hold muscle while weight comes off. Split the daily amount into two meals a day for an adult dog — morning and evening — rather than one large meal, because two smaller meals are easier on digestion and keep the dog feeling fed through the day. Feed in a quiet place, at the same times every day, and take the bowl away after twenty minutes.
Keep treats under 10% of daily calories, and count them: use the dog's own food as treats, or a single low-calorie treat, and stop giving food from the table. If there are children in the house, agree together who feeds the dog and what treats are allowed, because a dog fed by three people is fed three times. Do not leave food down all day: free feeding makes it impossible to know how much the dog has eaten, and it hides appetite changes that are often the first sign of illness. The free feeding vs scheduled feeding for dogs guide explains why scheduled feeding works better for weight loss.
Step 4: build exercise up
Food is most of weight loss, but exercise matters too, because it keeps muscle, burns calories, and keeps the dog happy. An overweight dog should build exercise up gradually — short, frequent walks or play sessions rather than one long weekend hike, because a heavy dog that is suddenly asked to run will strain its joints. Start with what the dog can do comfortably, add a little each week, and watch for stiffness or tiredness the next day: a dog that is stiff the day after exercise has done too much, and the next session should be shorter.
For dogs, walking is the safest start: two or three short walks a day, on flat ground, building up the time over weeks. Swimming is excellent for an overweight dog, because the water takes the weight off the joints — but only where the dog is safe and supervised. For cats, play is the exercise: short, frequent play sessions with a toy the cat can chase and catch, a scratching post, and climbing places. The best exercise for overweight dogs guide gives a safe build-up plan, and the exercise needs calculator puts exercise in the context of age and size.
Step 5: handle plateaus and keep the weight off
Weight loss is rarely a straight line, and a month with no change is normal — it is a plateau, not a failure. When a plateau happens, cut food by about 10% and keep going for another month, rather than abandoning the plan. If weight still does not move after two months, or if the dog is lethargic or off its food, see a vet. Do not cut food by a large amount at once, and do not change food every few weeks: a weight-loss plan needs at least two months before it can be judged, and a food changed after two weeks has not had a fair trial.
Once the target is reached, do not go back to the old amount: a dog that has lost weight needs less food than it did before, because a lighter dog burns fewer calories. Keep the food measured, keep treats under 10% of daily calories, keep exercise daily, and keep weighing monthly for life. A dog that is weighed monthly and fed a measured amount will hold its weight; a dog that goes back to food by eye will put the weight straight back on. The obesity in dogs guide covers the health risks of putting the weight back on, and the dog body condition score chart shows the nine-point scale to use for life.
For related reading, see the how to help a dog lose weight safely guide, the best food for overweight dogs guide, the how many calories to lose weight for dogs guide, the best exercise for overweight dogs guide, the dog ideal weight calculator, the dog body condition score chart.
Frequently asked questions
What is a good weight-loss diet plan for a dog?
Slow, steady, and simple: weigh the dog, set a target with your vet — usually 10 to 20% below the current weight to start with — feed a measured amount at about 1.1 times the resting energy requirement, keep treats under 10% of daily calories, build exercise up gradually, and aim for about 1% of body weight per month. Weigh monthly and adjust by 10% at a time.
How many calories should my dog eat on a weight-loss plan?
As a starting point, about 1.1 times its resting energy requirement (RER), where RER equals 70 times body weight in kg to the power of 0.75. A dog of 10 kg needs about 435 calories a day to lose weight. Adjust by monthly weigh-ins, and ask your vet to set the target for a dog that needs to lose a lot of weight.
How fast should my dog lose weight on the plan?
A commonly cited safe target is about 1% of body weight per month. That sounds slow, and it is — but slow weight loss is the kind that stays off, and fast weight loss loses muscle as well as fat. In cats, rapid weight loss can cause a serious liver problem, so slow is especially important for cats.
What if my dog's weight stops falling?
A plateau is normal — weight loss is rarely a straight line. Cut food by about 10% and keep going for another month, rather than abandoning the plan. If weight still does not move after two months, or if the dog is lethargic or off its food, see a vet.
Should I use a weight-loss food?
A weight-loss food helps, because it carries fewer calories per mouthful, less fat, more fibre so the dog feels full, and enough protein to hold muscle. But feeding less of a normal complete and balanced food also works, with your vet's agreement, as long as the amount is measured and the dog is weighed monthly.
How do I keep the weight off once it is lost?
Do not go back to the old amount: a dog that has lost weight needs less food than it did before, because a lighter dog burns fewer calories. Keep the food measured, keep treats under 10% of daily calories, keep exercise daily, and keep weighing monthly for life.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.