Can kittens eat adult cat food?

All cat owners wondered what would happen if we fed our kittens adult cat food, and some of us probably did feed our kittens adult food until we learned better. I must be honest and say that I did until I was educated by the veterinarian…

And if you are reading this article you probably want to find out too!

Yes, i fed my kitten adult cat food! 😔
When I rescued Dobby and he still looked like a kitten I must be honest and confess that buying him kitten dry food seemed like I was spoiling him because he deserved it, not because it was crucial! As soon as he started looking like a small version of an adult cat I started buying normal senior cat food for him, without knowing it’s too early to introduce him to that diet. And it worked, for a while! He still grew fast and looked healthy, was very playful, and I never had any health problems with him. After I rescued Dot and got her through the process of bottle-feeding, transitioned her to wet kitten food, and while waited for her to be ready for the dry food one day she just started eating Dobby’s adult food and I just let her eat it!
kitten eats dry food
I know… Bad mom… But I didn’t know any better! It all ended with her getting diarrhea and losing some weight, then Dobby getting diarrhea too. After we took them to the vet and got them all better, we found out lots of useful information that all cat parents should know about why it’s so important for kittens to have a properly formulated food diet. 

Do you want to know what we learned from the vet? Keep reading! 

Can kittens eat adult cat food?

Yes, kittens can eat adult cat food, but they definitely shouldn’t! 
It is okay to eat adult cat food once in a while, but not on a daily basis and not long-term. Why? 
Kittens grow fast and develop every day, which means they require high-energy-based food that provides the right amount of calories, proteins, fatty acids, and vitamins necessary for their healthy growth. Unfortunately, adult cat food does not meet all the essential nutrients that a kitten needs in its diet and can cause your kitten to become malnourished. 

Feeding a kitten only senior cat food all the time will cause him harm and may put his health at risk in the future by not providing all the minerals and vitamins needed to grow into a healthy cat. Cats younger than 12 months old are still considered kittens and should be fed propper kitten food all this period until they are ready to be transitioned to adult cat food. 

What is the difference between kitten food and adult cat food?

The difference between kitten foods and cat foods is only in the number of calories found in the kitten formula (which should be almost triple as much as in adult food), and also the higher amount of protein and fatty acids which is needed for the rapid growth of a kitten. Kitten formula sometimes may even include higher levels of calcium and phosphorus, but the water, magnesium, taurine, and other minerals are mainly the same as in adult cat food. The senior cat food has a lower calorie intake and often contains vitamins and minerals to help with good and healthy aging.

Here is everything you need to know about a kitten’s different dietary requirements.

Calories & Proteins

Kittens need more calories in their food to provide them with the appropriate energy to be very active and playful all day, about 3 times more than a senior cat. 

To support their explosive-growth, the good development of every cell in their body and their overall strength kittens should have at least 30% of their calorie intake from animal-based protein. Kitten food usually contains up to 15% more protein than adult cat food.


Fats also supply extra energy for your playful kitten and are essential for delivering fat-soluble vitamins in their growing body. Dietary fats and fatty acids like omega-3 and omega-6 are playing an important role in many organ functions and maintaining good overall health and growth. Kitten formulated food contains the specific eicosapentaenoic and docosahexaenoic acids from omega-3s that an adult cat food doesn’t.

Minerals & Vitamins

Minerals like Calcium, Phosphorus, Potassium, and Magnesium help with the growth of strong bones and teeth. Vitamins like E and Selenium help develop the kitten’s immune system. Kittens need nearly twice as much Calcium in their food than adult cats. 

What would happen if you feed your kitten adult food regularly?

kitten eats dry food 1

By feeding your kitten adult cat food regularly you deprive them of the essential minerals and nutrients they require to grow because they can not be found in the adult cat food. If their diet is lacking the proper mineral-dense food they need for a long time, the kitten will most probably suffer from malnutrition and one or more of these symptoms: diarrhea and weight loss, muscular weakness, poor condition, claw growth, and fur quality, dry and scaly skin, weak immunity and eyesight, gingivitis. This will also determine antisocial behavior, agitation, and overall tiredness of your young kitty. 

I’ve learned this the hard way!

my kitten’s diarrhea experience
I didn’t know that Dobby was still a kitten until the age of one year old, and he should still eat kitten food, and definitely, I did not know why Dot should not eat adult cat food at all at her age! Only after they both got diarrhea, and Dot ended up losing some weight and looking a bit skinnier, that we took them to the wet and found out how harmful it can be for kittens to eat adult cat food on regular basis!
sad kitten
I felt so bad, thinking I was a bad mother and I should know better, but the vet assured me that it was easily fixable and Dot didn’t get to a malnourishment stage because I didn’t feed her the adult food for a long period of time and I was still giving her wet food. They both had to take some pills for diarrhea and eat special gastrointestinal food with probiotics for two weeks to help restore their gut health. Since then they are growing happily and strong every day!
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What does a malnourished cat look like?

A malnourished cat will start to look skeletal if you continue feeding it the wrong food. The spine and shoulder blades will be obvious through the skin and their bones will protrude due to the poor development of the muscles and lack of fat covering his body, especially on the belly. Their stomach will become smaller and less able to absorb the nutrients in the food and will have a noticeable sucked-in-belly appearance. Their hip bones and rib cage will also be very evident. 

A healthy cat should have a well-proportioned body, a noticeable waist behind the ribs when you look at your cat from above, and a small paunch of fat on their abdomen, but also their tummy doesn’t go past their rib cage when you admire your cat from the side. When you touch your fluffball you should be able to feel their ribs, but they should not be bony and rather covered with a bit of fat. 

healthy cat
Healthy cat ❤️
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Malnutrition can be reversed, but a prolonged period of untreated malnutrition will have general long-lasting effects on the general health and immunity system of your cat and can cause organ failure, especially for the liver. 

What if you feed your adult cat with kitten food regularly?

If adult cats eat kitten food it won’t harm them, but eating it long-term will have them consume more calories, and because of the higher protein and fat content of the kitten formula, this could lead to obesity in a mature cat.

Adult cats are normally not as active as kittens and they don’t grow at a faster rate anymore, so they need fewer calories in their diet. Senior cat food is formulated to maintain a steady healthy body and slowly ease them into aging. 

How to feed your kitten and adult cat safely?

To safely give food to your different aged cats, feed your kitten and the adult cat in separate rooms, and don’t leave food on the floor accessible to them at all times (free-choice feeding). This is the best solution until the kitten is older than twelve months and they can be fed together. As an alternative solution, you could choose a type of food suitable for cats of all ages, but firstly, talk to your vet about a food option like this, so they can point you in the right direction. The commercial cat foods that are labeled for all ages, based on their content they may still cause obesity in adult cats and not meet your kitten’s nutritional needs. Or at least make sure it is approved by AAFCO ( American Association of Feed Control Officials), a group of state and federal officials that approve and control pet food. 

Kittens eat anything and are very curious, so the adult food might be appealing for them as it comes in more flavors, but senior cats also love more to eat kitten food if given the choice. Feeding them together in separate bowls may result in them choosing to eat each other’s food.

cats eating

A type of food appropriate for all cat ages might be good if your different age cats are used to free-choice feeding. Free-choice feeding means your cats have food and water available all the time and will eat when they want and usually only how much they need. This reduces stomach bloating, usually a common result of eating fast when food is provided. Free-choice feeding also helps with the recovery of underweight and slow-growing kittens. 

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The free-choice feeding method is not recommended for obese kittens or cats.   
If you want to know how much food you can give your fur babies check the recommendations on the manufacturer’s brand label and adjust to feeding portions if and when necessary. 

Wet food and treats

It’s ideal for very young kittens to have some canned food in their diet, especially because they can’t easily chew the dry food with their small teeth, and some wet food will definitely balance them into the right nutrition necessary for growing and playing. 

The recommended wet food feedings for a kitten that also eats dry food is twice per day, but if you are giving them only canned food then you should give them four times per day.

cat wet food

I feed my fluffballs both wet and dry food, to offer them all the benefits pawsible. Wet food aids in the health of the urinary tract, whilst dry food is good for removing dental plaque when they chew it.

Treats are also beneficial for your kitten especially when trying to teach them how to follow a new behavior or routine and you want to reward them, or you just want to purely spoil them and keep them happy, but be careful, a treat should not have the caloric value more than 10% of your kitten’s total calorie intake per day. 

piece of advice
If you consider letting your kittens try some of your leftover food bites as a treat, know that some human foods like chocolate, caffeine, onions, garlic, raisins, and grapes are toxic for cats. Also, raw meat and eggs can contain parasites and harmful bacteria or Salmonella. Raw fish often leads to poor vitamin absorption and vitamin B deficiency, making your cat lose appetite or have seizures. Vitamin B deficiency may also lead to death. Cow’s milk causes diarrhea as over time kittens are losing the ability to digest it. 

Start them off with the right paw!

Do not forget
It is very important to provide a balanced and adequate diet for a kitten and very easy and necessary to just buy food specially formulated for them. Your kitten’s nutritional needs will change over time as their body slowly develops into adulthood, but by offering them the right nutrition for their specific age, you are optimizing their well-being and health for their entire lifetime without causing them any harm. 

And don’t worry, feeding your kitten some adult cat food once in a while will not affect his growth process and development, but remember that making it a regular food option will! 

We would love to hear your thoughts and experiences in the comments below!

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