Overweight in Dogs and Cats: How to Spot It and Help Them Lose Weight Safely

September 27 2026, by Michael van Wassem, 9 min reading time

Overweight is one of the most common, yet most preventable, health problems in pets. Learn how to recognise overweight in your dog or cat and help them lose weight safely.

A dog or cat that has "filled out a little" can look endearing, but extra weight is not a harmless bonus. It is one of the most common health problems in pets, and at the same time one of the easiest to prevent. In this article you'll learn how to recognise overweight in your dog or cat, why it matters so much, and above all: how to help your pet lose weight safely and healthily.

Short answer: is your pet overweight?

You don't need a chart of exact target weights to make a first assessment. If you can feel the ribs with light pressure on your dog's or cat's side, without pressing hard, and you can see a clear waist behind the ribs from above, the weight is probably in a healthy range. If you can barely feel the ribs, or only with firm pressure, and there's no visible waist, your pet is likely overweight. When in doubt, a vet or vet nurse can work out a Body Condition Score (BCS) in a few minutes: a scale from 1 (very underweight) to 9 (severely overweight) that's far more reliable than the number on the scale alone.

Recognising the signs of overweight

Because you see your pet every day, gradual changes are often noticed late. These signs help you look more deliberately.

The rib test: feel rather than just look

Place both hands flat against your pet's sides, at chest level, and gently run your fingers over the ribs.

• Healthy weight: you feel the ribs just under a thin layer of fat, similar to the back of your hand with fingers extended.
• Mildly overweight: you need to press firmly to feel the ribs, similar to your palm.
• Overweight/obese: you can barely or no longer feel the ribs, similar to the top of your knuckles.

Waist and belly line

Look at your dog or cat from above: is there a clear waist behind the ribs, or does the body run straight through with no narrowing? Check from the side too: at a healthy weight, the belly line slopes upward towards the hind legs. If the belly hangs down or the line runs flat, that points to overweight.

💡 Tip: take a photo of your pet from above and from the side once a month, always in the same way. This makes gradual changes visible that are easy to miss day to day.

Causes of overweight in dogs and cats

Overweight rarely comes from a single big mistake, but usually from the sum of small habits.

• Too many calories: the recommended amount on the packaging is an average. Your pet's actual energy needs depend on age, breed, activity level and whether it has been neutered or spayed.
• Treats and leftovers that go uncounted: a small piece of cheese or a scrap from your plate seems harmless, but for a 4kg cat it adds up just as much as an extra burger would for a person.
• Neutering or spaying: after the procedure, many pets' energy needs drop by roughly 20 to 30%, while appetite often increases. The portion needs to come down to match.
• Less exercise: due to age, joint problems, a busy owner's schedule, or simply a laid-back nature.
• Underlying health issues: conditions such as hypothyroidism in dogs can encourage weight gain. If your pet keeps gaining despite an adjusted diet, discuss this with your vet.

Health risks of overweight

Overweight is more than a matter of appearance. In dogs and cats, it increases the risk of:

• Osteoarthritis and joint problems, from the constant extra strain on the joints
• Diabetes mellitus, especially in overweight cats
• Heart and breathing problems, and reduced tolerance of heat or exercise
• A higher risk of complications during surgery and anaesthesia
• A shorter life expectancy

That last point isn't just an assumption. In a long-running US study of Labrador Retrievers, one group of dogs was kept at a healthy weight for life while their littermates were allowed to eat freely. The leaner dogs lived, on average, almost two years longer and developed chronic conditions such as arthritis noticeably later in life. It confirms what vets have long observed in practice: a healthy weight is one of the biggest, most underrated gifts you can give a pet.

Losing weight safely: the step-by-step plan

Rapid weight loss isn't the goal for dogs or cats, and in cats it can even be dangerous (see the warning box below). Build it up gradually.

1. Step 1 – Get an objective weight check. Have your pet weighed at the vet's and get a Body Condition Score. Rule out underlying causes such as a thyroid problem before starting a diet.
2. Step 2 – Set a target weight and pace. A healthy rate of weight loss is usually around 1 to 2% of body weight per week. Losing weight too fast costs muscle mass rather than fat.
3. Step 3 – Calculate the right portion. Base it on the target weight, not the current weight, and weigh food on a kitchen scale rather than estimating with a scoop.
4. Step 4 – Reduce the portion gradually. Cut the amount down in small steps of a few percent per week rather than halving it in one go.
5. Step 5 – Add exercise and enrichment. More activity supports weight loss, but it doesn't make up for an oversized portion.
6. Step 6 – Weigh every two to four weeks. This lets you adjust the portion in time and track progress.

⚠️ A note on cats: never let an overweight cat suddenly eat much less or stop eating altogether. Cats that lose weight too fast or too much are at risk of hepatic lipidosis (fatty liver disease), a serious and potentially life-threatening condition. Always introduce a diet gradually in cats, and contact your vet straight away if a cat refuses to eat.

Adjusting the diet: what to watch for

Simply feeding less of the same food often doesn't work well: your pet then also gets less protein, vitamins and minerals, even though preserving muscle mass matters most while losing weight. Purpose-made light or diet food is designed to contain fewer calories while keeping protein and fibre the same or even higher, so your pet feels satisfied while losing weight. Also keep in mind:

• Treats count too: include treats in the daily calorie total, or replace part of the kibble with vegetables such as cucumber or carrot pieces (dogs) as a low-calorie reward.
• Several small meals: especially for cats, splitting food into 3 to 4 small meals keeps hunger better under control than one or two large portions.
• Encourage slower eating: pets that wolf down their food in a few bites feel full less quickly. A slow feeder toy for dogs slows down eating and leads to a calmer, more satisfied feeling after a meal.
• Ask your vet if unsure: for cats with a clear tendency to overweight, there are dedicated diet foods for cats prone to weight gain, which support gradual, safe weight loss.

More exercise and enrichment

Exercise alone doesn't solve overweight, but it speeds up weight loss, preserves muscle mass and keeps joints supple.

• Dogs: build up extra walking minutes gradually, especially if your dog already has joint problems. Spread two or three shorter walks through the day rather than one long, demanding session.
• Cats: cats naturally move in short, intense bursts of hunting behaviour. An interactive toy for cats taps into this natural instinct and adds extra activity without it feeling like "exercise".
• Food puzzles for both: a food puzzle or snuffle mat makes your pet work for its food. That burns energy, slows down eating and provides mental stimulation, which reduces boredom and boredom-driven snacking.

Common mistakes when losing weight

1. Estimating food instead of weighing it. A "cup" of food can vary by up to 20% depending on how full you scoop it.
2. Not counting treats. Treats can easily make up 20 to 30% of daily calorie intake for small pets.
3. Cutting back too much too fast. This leads to muscle loss, extreme hunger and, in cats, health risks.
4. Watching only the weight, not body condition. Muscle weighs more than fat; the rib test and waist remain at least as important as the number on the scale.
5. Stopping once the weight looks right. Without a long-term adjusted portion, the weight often comes back just as quickly.

When should you see a vet?

Contact your vet if:

• you're unsure about the target weight or the right daily portion;
• your dog or cat keeps gaining weight despite an adjusted diet;
• a cat suddenly eats less during a diet (risk of fatty liver disease);
• there are additional signs such as excessive thirst, tiredness or breathing problems, which can point to an underlying condition such as diabetes or a thyroid problem.

Frequently asked questions

How fast is it safe for my pet to lose weight?
For most dogs and cats, a guideline of around 1 to 2% of body weight per week applies. Losing weight faster increases the risk of muscle loss and, in cats, liver problems.

Is light food always the answer?
Light or diet food helps most once portion size and treats are already under control. Without adjusting total calorie intake, switching to light food alone won't solve the problem.

Can my dog or cat go back to normal food after losing weight?
Once the target weight is reached, you switch to a maintenance portion, which is usually still somewhat lower than the portion that led to the weight gain in the first place. Keep weighing regularly to catch any renewed weight gain early.

Are some breeds more prone to overweight?
Yes. Breeds such as the Labrador Retriever, Beagle and Basset Hound in dogs, and the British Shorthair in cats, are known to be more prone to overweight, partly due to lower energy needs or a strong appetite. Prevention matters even more for these breeds.

Summary and conclusion

Overweight in dogs and cats usually develops gradually and stays unnoticed for a long time, even though it's one of the biggest risk factors for joint problems, diabetes and a shorter life expectancy. The rib test and the waist give a more reliable picture than the number on the scale alone. If you start a weight-loss plan, do it gradually: weigh food accurately, count treats, consider specific diet food where needed, and build up extra exercise slowly. If you're unsure about the right pace, or your pet keeps gaining despite every adjustment, bring in your vet. A few kilos less can make the difference for your pet between a painful and a comfortable old age.

Tags

Gezondheid & Preventie Honden Katten Kennisbank Voeding

• Share on:
• WhatsApp
• Deel
• X
• Pin it
• Messenger
• Email