If your cat is a little underweight or needs to gain weight to reach a healthy Body condition score (BCS), you’re not alone - many cat parents find that traditional feeding guidelines and generic portion sizes don’t work for every cat. That’s where our fresh, personalised meals really make a difference.
Unlike one-size-fits-all diets, KatKin is built around tailored portions and high-quality, high-calorie recipes that help cats reach their ideal weight - even those with smaller appetites. Here’s why it works so well.
1. Personalised portions - right calories, every day
Every KatKin plan starts with your cat’s unique profile - age, weight, activity level and body condition score. This data is used to calculate the exact number of calories your cat needs daily.
Our calculator will take into account body condition score (alongside age, weight and activity level) to work out how many calories your cat will need to reach their ideal body weight. So if you let us know your cat is 'skinny' but 'inactive' we'll make sure to take these into consideration when their portion is chosen.
Because calories are tailored to your cat’s needs rather than generic serving sizes:
You don't have to work out your cat's recommended portions if they need to gain weight. We'll do all the maths for you.
Portion sizes are precise so your cat gets just the right amount of energy and nutrients without guesswork.
Cats need to put on weight safely and slowly, and our portion calculator keeps this in mind.
2. High calorie density recipes for cats with smaller appetites
Here at KatKin, all of our recipes are made with 100% fresh, human-quality meat, gently steam cooked and frozen to preserve nutrition - with no grains, fillers or artificial ingredients.
Our 7 different recipes vary in calorie density depending on the ingredients in the meat (for example, pork tends to be more calorie-dense than chicken). This also means the weight of our portions vary too: 200kcal of Cluck weighs more than 200kcal of Oink.
Our recipes with high calorie densities are:
Mooo
Baaa
Oink
These recipes all weigh less per 100kcal than Cluck, Gobble, Quack and Splash.
This naturally high calorie density means:
Cats with smaller appetites may benefit from our high-calorie-density recipes, as they'll get the right amount of calories in a smaller portion of food (compared to our lower-calorie dense meals such as Cluck).
A smaller portion can still meet their calorie goals, increasing the likelihood your cat will finish their meal.
This is especially helpful for cats who may feel full quickly, or have smaller appetites, yet still need to gain weight.
All of our recipes are complete and balanced, so you can rest peacefully knowing that your cat is getting the right amount of food for them, no matter how small their portions seem.
3. Balanced nutrition built for carnivores
Cats are obligate carnivores - meaning they thrive on meat. KatKin’s fresh food replicates this ancestral diet, offering:
High protein from real meat - which supports muscle maintenance and growth.
Natural fats - a concentrated energy source that contributes to healthy weight gain.
High moisture content - supporting hydration and digestion.
This balance helps ensure that cats not only eat enough calories, but make the most of every one through efficient digestion - crucial for cats that are underweight.
👉 We include fat in our recipes, read more about why this is part of a healthy + balanced diet for cats here.
4. A variety of recipes to tempt fussy eaters
Meal acceptance is essential for cats who need to gain weight, especially if they have smaller appetites or pickiness around food. At KatKin, we offer a range of recipes from chicken and beef to fish and pork-based recipes - making mealtimes more exciting and appealing to even the fussiest cats.
You're in control of your cat's recipes, so if they like variety, they can be served a different recipe at every mealtime.
Or if they're particularly fussy and love just one type of meat, they can enjoy one recipe for every meal while still getting all of the nutrients they need.
👉 Click here to learn how to update your cats recipe selection in your account.
5. Easy to update as your cat changes
Cats’ calorie needs don’t stay the same forever - and that’s actually a good thing.
You KatKin account makes it simple to adjust your cat’s profile as their weight, body shape and activity level change over time, so their portion size can evolve too. This flexibility is especially useful for cats on a weight-gain journey.
Why updates matter
Your cat’s
weight
body condition score (BCS)
lifestyle
and activity level
all influence how many calories they need each day. By keeping these details up to date in your account, our calorie calculator will suggest the most appropriate portion size for your cat’s current situation - whether they’re still building weight, maintaining a healthier weight, or shifting between categories such as skinny to just right.
It’s important to know that here at KatKin we won’t automatically change portion sizes without your approval, since doing so can impact your plan price. Instead, after you update your cat’s details, the system will suggest what portion size might suit them best, and you can choose whether to apply it.
When to update your cat's details
Regularly - even small fluctuations in weight or behaviour can affect calorie needs.
After vet visits - if the vet reports a noticeable weight change, updating it helps keep portions accurate.
When appetite or activity changes - more active cats may need more calories, while less active cats may need adjustments to avoid overfeeding.
Kittens - Kittens grow and change constantly, it's best to update their details as often as you can during their first year. Kittens need more calories than adult cats, and our calculator will take this into account.
How to update
You can update your cat’s details easily in your KatKin account by navigating to Manage plans → My Cats and editing fields such as weight, body condition score and lifestyle.
After saving, scroll to daily calories to see a new suggested calorie amount, and then choose Change tray size if you want to apply that portion.
This approach ensures your cat’s plan stays fully tailored as they make progress - giving you confidence that the food they’re eating continues to support healthy weight gain and overall wellbeing.
Perception vs Reality
In the UK, 38% of cat owners perceived that their cats were underweight in 2025.* But as fellow cat parents, we know how difficult it can be to accurately determine the body condition score of your cat - the actual % of underweight cats here in the UK is predicted to be much lower.
Before letting us know your cat is 'skinny', we recommend following our guide to determining the BCS (Body condition score) of your cat. It's important that we know the correct details for your cat, so we don't send portions that are too large.
If you're worried about your cat losing weight, read our teams in-depth article about causes (and next steps.)
🩺 It's important to note that our portion calculator doesn't take into account medical conditions, such as hyperthyroidism or diabetes. If your cat has a medical condition and weight is an important factor, we recommend reaching out to our Cat Experts and in-house Vet Team who can provide you and your vet with advice personal to your cat's situation.
Source: Cat's Protection, CATS Report UK 2025