My boyfriend thinks that if my 2 year old cat were to eat kitten food for 8 months - a year straight it wouldn’t affect him at all and that it would be healthy for him because kitten food has more calories and nutrients in it. And that if out 4 month old kitten were to eat regular cat food, it wouldn’t bother her at all. Can someone please list the affects that would happen to him. He’s never owned a cat before so he thinks that cats are like dogs and puppies when it comes to feeding. Pet's info: Cat | Domestic Shorthair | Male | neutered | 2 years and 4 months old | 10 lbs

So I agree that adult food should be fed to adult cats and kitten food should be fed to kittens. Kittens need more calcium and phosphorus to help them grow properly. They need more calories because they are usually more active than adult cats. Adults that eat kitten food for a long period will usually gain too much weight. If they become obese this can cause secondary problems like obesity and diabetes. Kittens who eat adult food occasionally will have growth abnormalities or poor weight gain. I hope this helps!