My dog is overweight: a safe, gradual feeding plan

By Josh · Reviewed and updated: 2026-09-17

Weight loss in dogs is not complicated, but it is slow, and almost all of it comes down to measuring what you feed and checking the result every couple of weeks. This page takes you through it in six steps, and tells you how long each stage should take so you can tell the difference between a plan that is working and one that has stalled.

Step 1 — Confirm it is actually overweight

Start with your hands, not the scale. Run them along the ribs behind the front legs, look at the waist from above, and look at the tuck from the side. If the ribs are hard to feel under a layer of fat and the waist has disappeared, the dog is carrying too much. The body condition score page walks through all three checks in a minute.

Do this before anything else, because the most common mistake in this whole process is deciding a dog is overweight when it is not, and then putting it on a diet it does not need.

Step 2 — Get a target weight

Your vet can give you a number in a few seconds, and that is always the best option, particularly if the pet is more than a little overweight. If you are working it out yourself, the body condition score converts to a percentage in fixed steps rather than a range: each point above ideal is equivalent to 10% overweight — BCS 6 is 10% over, 7 is 20%, 8 is 30% and 9 is 40% (AAHA nutrition and weight management guidelines).

Then estimate the target the way the guidelines do, by subtracting that percentage from the current weight rather than dividing by it. Their own worked example is a 45 kg Labrador at BCS 8 out of 9: 30% overweight, so the ideal weight is about 45 × 0.7 = 32 kg. Apply the same arithmetic to your own pet and you have a target to feed against.

Write the target down. A target you have not written down drifts, and so does the plan.

Step 3 — Work out the daily amount for the target, not the current weight

This is the step people get wrong. A dog on a diet should be fed for the weight it is aiming at, not the weight it is now — feed it the amount that maintains its current weight and it will maintain its current weight indefinitely. Put the target weight into the calculator and use the figure it gives you.

The calculator also produces a treat allowance for that target weight, which is where most diets quietly fail. Treats, table scraps, dental chews and the food used to hide a pill are all calories, and they are the ones nobody writes down.

Step 4 — Know what a safe rate looks like

Dogs can safely lose 1 to 2% of body weight per week. Faster than that and you risk muscle loss rather than fat loss, which is the opposite of the goal. The calculator above uses 1% by default — the slow end of that band — and shows you the full range in weeks so you know what "on schedule" looks like.

Cats are different, and this part is not optional. Veterinary guidelines put the safe feline rate at 0.5 to 2% of body weight per week — AAHA gives 1–2% as the ceiling and APOP uses 0.5–2% — and many clinicians start a cat near the lower end of that band rather than the middle. Two rules override everything else. A cat that refuses a reduced ration must not be starved into compliance: significant caloric restriction lasting 48–72 hours can cause hepatic lipidosis, which is frequently fatal, and overweight cats are at the highest risk. And if your cat is more than 20% above its target weight, that is a veterinary plan rather than a home one.

Step 5 — Measure, do not estimate

A diet that works on paper can fail in the bowl. If your measuring drifts by 10% — which is what a levelled cup scooped by feel typically does — a 187 g portion becomes 206 g, and the plan is running 10% behind without anything looking different.

The measuring page covers five methods ranked by accuracy, including how to work out your daily grams using only a bathroom scale. Whichever you use, use the same one every day.

Step 6 — Weigh in every two weeks and adjust in small steps

Weigh your pet every two weeks — weigh yourself, then yourself holding the pet, and subtract — and check the body condition score again. Then do one of three things:

What usually derails a dog diet

• Treats. The single biggest cause. Count them, cap them, or swap to something small — the treat page does the arithmetic.
• Other people in the house. A diet only works if everyone is feeding the same number. If two people feed the dog, write the daily amount on the food bin.
• Dog food that is not the dog's. In a household with more than one pet, the overweight dog is often finishing somebody else's bowl.
• The cat's food. Cat food is more calorie-dense than dog food and it is rarely measured.
• Starting too hard. A steep cut produces a hungry, miserable dog and an owner who gives up in week two. The safe range is deliberate: it is slow because slow is what lasts.

When to involve your vet rather than do it yourself

The honest expectation

A 5 kg loss on a 30 kg dog takes eight to seventeen weeks on a safe rate, and the first two are the hardest because the dog notices the change before the owner sees any result. That gap is where most diets fail. It is worth knowing at the start, so that week three feels like being on schedule rather than being stuck.

Once the target is reached, the work is not over: the calorie figure changes to a maintenance amount for the new weight, and weighing every two to four weeks during the maintenance phase is the standard recommendation. A growing number of veterinary teams also score body condition at those check-ins, because a stable weight can hide a shift from muscle to fat. Dogs that regain the weight they lost almost always do so because the plan stopped when the target was reached rather than because it failed.

Frequently asked questions

Calculate the daily amount for the target weight →
Check the body condition score →
Work out the treat allowance →