Creating a weight loss plan for cats

4 September 2023 - 6 min read
An angry looking grey and white cat is getting measured using a measuring tape.

Is your cat looking a little heavy? Then you may need to investigate working with your veterinarian to create a weight loss plan for your kitty. Lots of cat parents face the mammoth task of managing their cat’s weight to ensure their long-term health and wellbeing.

“I spent five years working in a feline only clinic, so I've seen a fair number of cat owners become stressed by the topic of weight management,” says Dr Kirsten Ronngren, consulting veterinarian for ManyPets. “I can definitely understand why people feel that way - it's an emotional topic and over recent years overweight cats have become relatively normalised.”

For this guide, we’ve pulled together expert advice from veterinary experts on how to create the right weight loss plan for cats - as well as speaking to cat dad Howard - who has experience of working with vets to help his cat Dotty lose weight.

Why should my cat have to lose weight?

Unfortunately, carrying excess weight can lead to a range of health issues for cats. These include:

  • joint problems (arthritis);

  • feline lower urinary tract disease (FLUTD);

  • diabetes;

  • cardiovascular disease;

  • and a decreased quality of life. 

Overweight cats are also known to display signs of obesity - such as lethargy, difficulty breathing, or an altered physical appearance.

Howard - a UK cat dad - said that he first noticed that his cat Dotty was struggling with weight when she became a little inactive. “Although she could go outside, Dotty often opted instead to snooze in the house. This led us to notice that she was getting a bit of a tummy on her!”

It’s also important to note that some cats are more likely to suffer from unwanted weight gain than others - particularly indoor-only neutered cats.

Two profiles (each a top view and side view) of a cat sit side by side. The one on the left shows a cat at an ideal weight; the one on the right shows an overweight cat.

What's the first step in a cat weight loss plan?

Working with a veterinary professional is very important when it comes to weight management.

Consulting with your regular veterinarian, a veterinarian specialising in nutrition, or a certified pet nutritionist is recommended, as they can provide personalised advice based on a cat’s specific needs. 

To start the process, a comprehensive assessment of a cat’s health will be conducted to rule out any underlying conditions that may be contributing to weight gain, ensuring a safe and effective weight loss journey.

Vets may also ask you to create a food diary.

“I’ll often ask my patients to record every meal, treat and even little scraps in a notebook. Honestly, using this can often reveal where the problem actually lies! It’s not uncommon for pet owners to not realise how many calories they’re feeding every day until they have to measure and record it.”'

If a cat is only a little overweight, a veterinarian may look at the food diary and see that nutritional balance looks adequate – but may see that there are a few too many treats or overall calories in the mix. The solution to your cat’s weight loss could then be as simple as cutting back on treats or making a small decrease in the amount of regular food fed each day.

What amount of food should I be feeding my cat to help it lose weight?

If first inspections show that your pet’s weight is of a concern, then a veterinarian might start discussing a weight loss plan.

This plan often dictates the amount you should be feeding your cats - and that begins with understanding your kitty’s energy requirements and how many calories it should be fed to meet them.

This bit requires quite a bit of maths - so strap in for a quick lesson in veterinary science.

Vets start by calculating a cat’s Resting Energy Requirement - or RER. That is the number of calories required for essential functions such as digestion, respiration, and cardiac and brain activity when the pet is at rest in a stable temperature. 

To calculate this, we use the following standardised equation devised by veterinary scientists:

RER = (Cat’s Body Weight in kg^0.75) x 70

Those numbers may seem random, but this equation is derived from the estimated metabolic needs of an animal based on the given weight. 

The following chart provides general calorie requirements based on some standard cat weights:

Cat's Weight (kg) RER (calories)
2 118
4 198
6 268
8 333

The next step involves calculating a cat’s Maintenance Energy Requirement - or MER. This daily calorie allowance takes into account the pet’s lifestyle and factors that impact the amount of energy they might use.

After calculating RER, factors like life stage and activity level are taken into account to establish the MER. Adjustments are made based on whether your cat is neutered, prone to obesity, indoor or outdoor. The goal is to gradually reduce your cat’s calorie intake while ensuring they receive the necessary nutrients for optimal health.

A vet will calculate this MER factor using a standardised list of factors. They will then use this to multiply your RER value and produce the number of calories your cat should be consuming per day.

Life stage factors MER factor
Neutered adults 1.2 - 1.4
Intact adult 1.4 - 1.6
Inactive or obese prone 1.0
Weight loss 0.8
Gestation 1.6 - 2.0
Lactation (based on number of offspring and weeks of lactation) 2.0 - 6.0
Growth 2.5

It’s important to point out that these calculations are just a starting point. Any individual animal’s needs can absolutely vary from the calculated goal. It’s important that weight loss plans are tailored to an individual pet’s needs and health and adjusted based on the pets response during the weight loss process.

What should I be feeding my cat to help it lose weight?

drawing of stomach with food in it

After you’ve worked with your vet to figure out the daily calories your cat should be getting, it is then time to thrash out a safe and nutritionally balanced diet to make sure your cat is still getting the appropriate proportion of nutrients it needs to stay healthy.

If your pet only needs to lose a small amount of weight, it may just be a matter of adjusting the amount of their current diet you are feeding. 

For cats with larger weight loss goals, vets may recommend commercial diets formulated for weight loss, or you can work with a professional to create home-cooked meals that meet your cat’s needs. 

Generally a cat’s diet will have a higher proportion of protein than that of a dog’s plan - this is normal and is due to their specific nutrition needs.

Slow and steady weight loss - around 0.5-1% of their body weight per week - is the aim, achieved through controlled calorie intake and nutrient-rich foods.

Overall, a safe and nutritionally balanced diet should replace high-calorie treats and unhealthy table scraps. There are definitely healthier and more appropriate options to use so that your cat can still be rewarded, while still following a tailored weight loss plan!

“After figuring the right portion size for Dotty, her weight loss journey went perfectly,” said Howard. “After a few months, her next vet check-up showed that her weight was fine.”

Does exercise help my cat lose weight?

While exercise plays a role in weight management, it's important to note that controlling caloric intake is often the primary focus for cats struggling with obesity. 

That’s probably a good thing - as unlike dogs, it’s not quite as straightforward as strapping a leash on a cat and taking it for a trot around the block.

However - it’s worth trying to encourage your cat to move around a bit more as exercise does help promote a healthy feline lifestyle when combined with the right dietary plan set out above.

Though it can be a little bit of a challenge to get your cat moving, there are some things cat parents can do at home to help introduce a touch more activity to their daily routine. 

  • Instead of having one spot for your cat’s feeding time, plant its bowl or matt at different locations around the house. This means your cat has to prowl and find its food - tapping into its feline hunting instincts and using a bit of energy to do so.

  • Consider putting food up high - on cat trees, or desks - where it is safe to do so. This will encourage your cat to jump up for its food!

  • Investigate feeding toys - like balls and mats - to create an interactive (and active!) dining experience.

  • Use cat toys - like strings, feathers, squeaky mice - to encourage short bursts of activity. Not only is this a great time to bond with your pet, it also stimulates its hunting instincts and need to catch prey.

Do I have to keep working with the vet to help my cat lose weight?

Young Hispanic female cat owner sitting and waiting for her appointment with the vet. She has a beautiful gray cat in a cage.

Ongoing collaboration with your veterinarian is crucial throughout your cat’s weight loss journey. Not only do regular check-ins allow for assessment of progress, it also facilitates small adjustments over the course of action as well as support if fluctuation occurs.

Veterinary teams might also use monitoring tools like body weight, body condition score (or BCS), and body fat percentage to help track results and guide modifications to the plan. 

Typically - if the steps above are followed - a kitty might reach their ideal body weight within six to eight months. 

By maintaining a partnership with your vet, you ensure that your cat’s weight loss plan remains effective and aligned with their evolving needs.

Keep the faith - the weight loss journey is worth it!

Embarking on a weight loss journey with your cat may seem daunting, but with the guidance of a veterinarian and your dedication, positive results are achievable. 

Just like Howard, you can witness the transformation in your furry friend's health and well-being. 

“It definitely taught me that it’s super important to get your cat weighed regularly,” added Howard.

Remember, every cat is unique, and a tailored weight loss plan ensures that your pet receives the individualised care they deserve. 

Through the combined efforts of owners, veterinarians, and pets themselves, we can pave the way to a healthier, happier life for our four-legged companions.

Cat insurance can help

Diagnosing, treating, and managing weight-related health conditions can be complicated and costly, but cat insurance may help! Just make sure you insure your cat when they’re young so that chronic conditions may be covered instead of being considered pre-existing conditions.

Lewis Martins
Communities marketer

Lewis has worked in pet health since 2017. Before joining ManyPets in 2021, he led content production at VetForum and PetsApp. Lewis has collaborated with some of the world’s biggest vet groups and suppliers to write educational articles for vets and pet parents. His Instagram feed is 60% dogs, 40% cats.