Switching from Kitten Food to Cat Food: The Why, When, and How

Just like you definitely wouldn’t hand over adult food to sweet gurgling babies, kittens shouldn’t be fed adult cat food before they’re ready. That’s because cats have different nutritional needs depending on their stage in life.

As kittens, they eat nutrient-dense food that helps them grow, but as they near the end of their growth period, it’s important that their diets change to meet the demands of their new, almost adult bodies. Switching from kitten food to cat food—at the right time and in the right way—is the best way to do this.

Kitten food is designed to support rapid growth and development. In comparison to adult cat food, kitten food generally has:

• More calories, protein, and fat
• Adequate levels of docosahexaenoic acid (DHA), an omega-3 fatty acid that is important for brain and vision development
• Increased amounts of some vitamins and minerals
• Optimal calcium to phosphorus ratios

Weight gain is the biggest danger associated with continuing to feed kitten food to an adult cat. While a chonky cat might sound cute, a healthy weight is going to help your cat live a happier, healthier life!

The Association for Pet Obesity Prevention estimates that almost 60 percent of pet cats are overweight or obese, which puts them at increased risk for many health problems including diabetes, arthritis, and hepatic lipidosis (a potentially fatal liver disease).

In general, kittens should eat kitten food until they are around 90 percent of their adult weight. At this point, they are at their full adult height and just have some final filling out to do.

• Most kittens reach this milestone at about 10 to 12 months of age, making this the ideal time to switch to adult cat food.
• An exception to this rule may apply to large breed cats. Larger breeds, like Maine Coons, don’t reach maturity until they are 18 months to 2 years of age. Keep feeding these big kitties kitten food until they are at least 18 months old.

Always speak with your veterinarian if you have any concerns about when to switch from kitten to adult cat food.

Transitioning from kitten food to adult cat food must be done gradually. A cat’s digestive system is home to lots of bacteria and yeast that aid in the digestion of food, fight off potential pathogens, make vitamins and other nutrients, and bolster the immune system. These microbes must be kept happy!

When the diet is abruptly changed, gastrointestinal microbes may not have time to adjust, which can lead to signs of digestive upset including vomiting and diarrhea. Further, when suddenly faced with a new food many cats will refuse to eat. (Cats really aren’t big fans of change.)

Slowly transition your kitten to an adult diet over seven to 10 days as follows:

• Days 1 and 2, add ¼ of the new diet to ¾ of the old diet
• Days 3 and 4, add ½ of the new diet to ½ of the old diet
• Days 5 and 6, add ¾ of the new diet to ¼ of the old diet
• Day 7 to 10, complete transitioning to adult cat food (100% new food)

If at any point your cat loses their appetite or develops signs of digestive upset, you can go back to their old kitten food for a few days and then restart the transition at an even slower pace.

Here are some other ways to deal with difficulties transitioning from kitten food to adult cat food:

• If you’ve been feeding dry food to your cat, consider switching to wet food. Wet cat foods have a higher water content which is beneficial to their urinary health and weight management. It can also help with constipation. Some wet food to consider include:
  • Wellness CORE Signature Selects Shredded Boneless Chicken & Beef Entree in Sauce Grain-Free Canned Cat Food
  • Earthborn Holistic Chicken Catcciatori Grain-Free Natural Adult Canned Cat Food
• If you want to keep feeding dry food, try a higher quality option. Some premium dry cat foods to consider include:
  • Iams ProActive Health High Protein Chicken & Salmon Recipe Dry Cat Food
  • Hill’s Science Diet Adult Indoor Cat Dry Cat Food

When in doubt, always lean on help from your veterinarian. They are your best resource for answering specific questions about when and how to switch from kitten food to cat food, switching cat food in general, and about your cat’s overall health and well-being.

Can kittens eat adult cat food?

Younger kittens should primarily eat nutritionally complete and balanced kitten food and should stick to kitten food until they are 90 percent grown. Many growing cats can begin eating adult cat food when they are around 10 to 12 months old. Larger breeds, such as Maine Coons, can eat adult cat food at around 18 to 24 months of age.

Can you switch kitten food brands?

You can switch kitten food brands. In fact, it is a good idea to switch to a higher quality kitten food if you have concerns about the nutrition your kitten is getting from their current diet. Just be sure to gradually make the switch.

How long can kittens keep eating kitten food?

Kittens can keep eating kitten food until they are almost full-grown. This usually happens when they are around 10 to 12 months old.

An exception is larger breeds of cats, like Maine Coons, who don’t stop growing until they are 18 months to 24 months old. Large breed kittens can keep eating kitten food until they are around 1½ to 2 years old.