Switching 11 year old cat to grain free food - is it safe?

I just got an 11 year old cat that has been eating Purina Kit n Kaboodle basically her whole life. I want to switch her to something healthier and grain free. I'm worried because she's eaten grain food for so long. Should I be worried about any digestive issues? I know cats can be sensitive and I've never switched a cat that has been eating the same food for so long. 

I could switch to a healthier brand that has grain in it as well if that's a better option. I can tell she's not very healthy because her fur tends to be kind of oily and just not as soft as my other cats who are very healthy and have been on good diets. Her ears are also very waxy and I've had them checked - nothing bad going on except a lot of wax.

Anyway, my main concern is causing her digestive distress or even something worse by switching to grain free after such a long time. 

Any help would be appreciated. Thanks. 

Hi Alofty - welcome to TCS!

Yes, it's perfectly fine to change foods and, the grain free will be much healthier for her.

I'd suggest doing it slowly.  Some cats can acclimate fast to a new diet (ours do), others not so much.  Cats do tend to get set in their ways about food routines.  If you mix in a small amount of the new food with the Purina, she probably won't even notice at first.  Little by little, give more of the new and less of the old mixed in.  Eventually, she'll be only eating the grain free and this would give her digestive system time to get used to the better food.

I switched my 14 (then 13) year old guy over to grain free a year ago, and he's doing great on it As sivyaleah says, it's important to go slow to let your girl's tummy adjust to the better quality food, but other than that you should be just fine

This arctic talks about switching from kibble to a different sort of food, but it has a lot of useful tips that apply to any dietary change [article="31138"][/article]

Thanks for your responses! I think I'm going to slowly switch her to Merrick Before Grain, it has been really great for my other cats. 

If you haven't I'd suggest you have a routine senior blood panel done to check all her levels and make sure that greasy coat isn't related to a health issues. Cats over 10 are prone to hyperthyroidism and kidney disease, and if caught early can live long lives. I'd high encourage you to not only switch her over to grain free kibble but consider moving her onto an all wet diet. Older cats really need that moisture to avoid future kidney issues and dehydration.