Originally Posted by Yosemite
You could change her to a good quality kitten food. Kitten food is a bit richer than adult food. Also although a good quality dry food will cost more you end up feeding less because of the quality.
We free feed dry food during the day and they get a can of wet for dinner. I've been trying various brands of wet that have no by-products and although they don't like them as much as the cheap junk stuff, they eat them and are starting to like them more now.
Our Mika is about 1.5 yrs. old and she is only 8 pounds and eats like a horse. Bijou is almost 2 yrs. old and he is 16 lbs. and does not eat as much as Mika - go figure.
I agree, get your cat on a good diet that has meat as the first ingredient. There are lots and lots of posts here, on which foods to feed cats.
I adopted an 8 week old kitten a couple of months ago that had different problems, including a bad cold and worms, she was also very malnurished and skinny. I got her on Iams at first, then later switched to Nutro Natural Choice kitten food because I learned the price difference wasn't big + it is a much better food. They carry it at PetSmart. She was treated for her illnesses too. In addition, I got her a supplement that's called Nutri-Cal, and this is a paste that contains large amounts of nutrients and calories. The vet said to give her 1 tsp a day. She put on weight very quickly, grew like crazy. She's now 4 mo. old and very healthy looking, and weightwise just great.
5 Lbs sounds very little for a grown cat. Then again, some cats are tiny. If you feel the hight of your cat is normal, then I'd say she's overly skinny. If she is just tiny in general, then use your judgement to whether she's too thin or not.