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How to Fatten Up a Cat

It has become more and more common to hear that cats struggle with obesity. Just like we see it in our human world, the feline world has the same tendency. However, underweight problems are not rare for cats either. To fight the symptoms, you need to understand their nature at first.

Why do cats have problems with weight? In order to understand how to healthily fatten up a cat, take your pet to a vet and consult the specialist on nutrition issues. According to the veterinarian practice, there may be a number of reasons why your kitty is losing weight. Here are some of them:

  • Problems with teeth. Senior cats may have bad tooth health and suffer from chewing food (especially dry), so check your boy’s/girl’s teeth before working out a plan how to fatten up a cat.
  • Parasites. It is an urgent problem for cats living outdoors. Worms cause too fast digestion of nutrients that do not have a chance to be properly absorbed into blood.
  • Active lifestyle. Your cat may be very active, so he needs more food to provide decent nutrition.
  • Hyperthyroidism. Specialists say, senior cats are prone to this illness, but if you are suspicious your cat is underweight, consult your vet to rule out endocrine diseases.

Step 1. Learn whether your cat does not weigh enough.

It may be not a big deal for experienced feline owners, but newbie cat parents need to know the algorithm. You cannot know for sure how much your cat should weigh, so let your veterinarian find out the ideal weight of your furry friend. However, you need to inspect your cat’s external appearance every now and then. 

You are not an expert in this matter, but there is a good working method to understand whether your kitty is too skinny. Looking at your pet’s body from above, you should see a cat’s figure with smooth shape of the body, with no ribs too much visible. There should not be a visible waist line or any other curves. Notice that cats look differently in winter and summer seasons being skinnier in hot weather and weighing more when it is cold outside. By asking your vet to give you pretty accurate figures of your feline’s perfect weight you will simplify the task of controlling your pet’s weight.

Body configuration of underweight cats.
Body configuration of underweight cats. Source.

Step 2. Diagnose possible health problems of your cat.

Once you have figured out your cat is underweight, it is high time to learn about his health. Are there any health reasons for that? How do you fatten up a cat without knowing your pet does not have any serious problem with health?

One of the most common problems is hyperthyroidism. The feline endocrine system resembles the human one, so some animals can suffer from a too high level of thyroid hormones in their blood. According to the Feline Nutrition Foundation, senior felines are likely to have hyperthyroidism. It does not really matter whether your cat is male or female or what breed he/she is.

Too high rates of hormone affects a feline’s brain and a cat owner can see certain change in his pet’s behavior. Cats become more active, they produce more feces, so there might be some lack of food for their new lifestyle, which leads to malnutrition and underweight problems. It should be your primary task to learn how to fatten up a cat with hyperthyroidism by asking your vet. Only a specialist can give you his professional advice on what’s good to fatten up a cat.

Step 3. Make sure your cat does not lose weight because of malnutrition.

If your cat has always been a picky eater, your need is to find the type of food he may like most of all. Experienced cat owners also have a number of hacks how to increase a cat’s appetite. 

But first, it is worth visiting your veterinarian to make sure if your feline’s skinny body is just a consequence of malnutrition. Pay your careful attention to how much protein, fat and vitamins your kitty gets from food daily. There is a table of recommended allowances for fats and proteins your feline should consume every day in a science-based guide for cat owners in America. Thus, kittens daily should get 10 g of crude protein and 4 g of fat, adult cats need 12.5 g of protein and 5.5 g of fat. For nursing cats expecting 4 cats in average protein should comprise 41 grams, and fat will boost up to 12 g. Knowing the recommendations it will be easier to plan a menu for your kitty providing her diet with enough nutrients.

Don’t forget to read our own guide on how much a cat should be fed.

Step 4. Control your cat’s eating behavior.

Another thing is if your cat’s food behavior has recently changed. Your first step should be to rule out the possibility of parasites. Let’s find out how you can organize your cat’s nutrition the right way. Thus, veterinarians insist on making this process calm and comfortable for your pet. Cats do not like any competition, let them eat slowly enjoying the food. This should be the first rule for those who are looking for the most optimal ways of how to fatten up a cat. Owning multiple cats you may face the problem of one cat stealing food from another cat (which leads to its malnutrition). This issue can be solved with the help of an automatic feeder for multiple cats or an electronic cat door.

Be careful in experimenting with your furry friend’s diet. Some cat breeders recommend certain human foods to fatten up a cat, though you need to consult your veterinarian on this issue.

Step 5. Fight anorexia if it is your cat’s case.

Heavy disease course and other kinds of nutrition malfunctioning can lead to anorexia, which is a serious illness for cats too. Of course, a pet owner cannot solve the problem without any professional help from a veterinarian. Recovering from anorexia is a long and demanding process that should be controlled by an expert. So there is definitely no advice on how to fatten up a cat fast when it comes to anorexia.

There are certain tips doctors give to pet owners to help them fight their cats’ anorexia. First is appetite stimulation. It is probably one of the best home remedies to fatten up a cat that can be reached by adding good-smelling ingredients to a cat’s food and even heating it up a little bit. Foods to fatten up a cat suffering from anorexia need to be strictly approved by your vet. 

Foods to Fatten Up a Cat

Once you have figured out what was the reason of your cat’s being underweight, you need to find the best foods to fatten up a cat. Professional associations of veterinarians recommend ready-to-eat commercial foods that can be found online, in supermarkets, and in pet shops. Such diets are well-balanced and prepared at factories with maximum control. According to the recommended allowances for cats of various ages find out what portion for your pet should be.

Keep in mind that cats of different ages, males, and nursing females should get different amounts of nutritive elements. Contact your veterinarian to learn how to fatten up a cat that had a litter. This category of adult cats is probably the most prone to underweight problems.

Do not forget about reading labels on feline food cans. Choose diets with natural ingredients (Solid Gold, Simply Nourish, and Soulistic are a good choice).

Also, you should be preferring wet and semi-moist feline food or mixed feeding against dry food only. Pay attention to the list of ingredients choosing products where meat or fish are the first-standing ingredients in a list.

It is also great to give a cat supplement for weight gain to fatten up a cat that is too skinny. If you have never tried any treats for your furry friend, it is worth trying some. They will give extra calories your friend may lack.

Read our general guide on choosing cat food or check the list of 21 healthiest cat foods we picked already and pay attention that a low carb high protein diet is not recommended for underweight cats.

Home Remedies to Fatten Up a Cat

Some pet owners tend to think that homemade food is even better for their favorites. But the first thing here should be understanding how well-balanced your home-cooked cat dishes will be. Of course, if you buy canned food, these menus are greatly balanced and enriched with vitamins and minerals. Obviously, veterinarians recommend wet and semi-moist food for cats with weight problems.

But some cats can be very finicky. Others tend to have rather strange eating behavior, so alternative ways to fatten up a cat may be the only way out. They include certain medical manipulations that are rather stressful for cats. To prevent such cases, pet owners sometimes try stimulating their cats’ appetite through delicious treats, extra flavors added to food, etc. As a rule of a thumb you should make sure all additives are safe and can bring no harm to your pet. 

Consult your veterinarian: some of them even give certain recommendations on cats’ food preparation at home. Remember that raw meat is not recommended for cats, though it is a great source of proteins and natural fats. Canned fish produced for humans is no good either. Be careful giving cow milk to your cat – most veterinarians do not recommend this product. As you can see, human food is not a good solution to fatten up a cat, so try to avoid products for humans. 

One of the greatest home remedies for finicky cats is to create pleasant atmosphere without irritating noises or stressful conditions around. Control your cat’s food bowl, its cleanliness and freshness of food in it.


How to fatten up a nursing cat?

Nursing cats need more nutritive elements, protein and fat in their food. The amount of protein should be 3.5 times higher than in food for an average adult cat. Choose cat foods containing organic meat and fish, with just a few ingredients on its label. 

How to fatten up a senior cat?

First, make sure your old furry friend does not have problems with teeth many senior cats have in their age. Second, see how active your cat is. Generally, senior cats start having problems with their bones, so their diet should contain enough protein – at least 6 grams of protein per every kilo of the pet’s weight.

How to fatten up a cat without making it constipated?

Cats eating only dry food may have problems with constipation. You should make your cat’s diet moisturous enough in order to avoid these problems. Veterinarians say that even ¼ tsp of moist food may be enough for your cat’s health.

How to fatten up a cat that won’t eat wet food?

If your cat likes kibbles, you can add just a little bit of chicken broth to his dry food. Make sure your pet drinks enough water after meal because it helps to digest the nutrients. However, do not let your furry friend drink too much water avoiding stomach pain. 

How to fatten up a starving cat?

The first rule here is not giving too much food at a time. It also refers to anorexia. Too much food in one portion will be fatal to your pet. The meal won’t digest properly and lead to stomach pain and inability to be absorbed. Give very small amounts of wet food to a kitty.

Why is my cat so skinny but eats all the time?

It is high time to consult your veterinarian. There may be a number of reasons. The first, your cat is just too active and uses much more energy than he gets from food. The second one is stress or endocrine problems. Worms may be the reason too. Take your cat to a specialist to rule out all of these problems.

Can you force feed a cat?

Only a specialist may decide whether a kitty needs to be force-fed. Do not practice such things at home by yourself. Any stress may be even more harmful for a pet. But if the case is serious enough, your veterinarian may take a decision to use a feeding tube, for example.

Do worms make cat skinny?

Yes, worms can make a cat skinny. Every time make sure your kitty eats from clean food bowls and the food is fresh. Visit your veterinarian for consultation.

What oil is good to fatten up a cat?

Choose oils containing so-called good fats. The most popular oils of this kind are olive, canola and coconut. Some organic wet foods contain decent levels of such oils. They provide nutrition and awake appetite.


Fattening up a cat with underweight problems may be a challenge for his owner. Generally, such eating behavior is accompanied by other health problems. Your first step should include consultation of a veterinarian, who will find out the problem of weight loss and give his practical recommendations. As a pet owner, you should understand that a caring atmosphere and no stress are probably the main conditions to overcome the problem.
Also, we have a guide for pet owners with the opposite problem. Read our article with the best low-calorie cat food written by Kimberly K. Baumgart RVT, LVT.


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