My 2 year old is under weight

My cat named Kitten is 2 years old and is under weight. I have tried switching her to Rachel ray's food and she just doesn't seem to want to eat.

She acts like she's in heat and my male cat follows her around , but this is been happening for about 2 or 3 months now.

She's really begun to make me worry.

Have you taken her to the vet? Loss of appetite is often a symptom that something is wrong, but your probably won't be able to identify it for sure without a vet visit.

In the meantime, getting calories in her is key. I use chicken or turkey baby food (Gerber or Beechnut jars are both good). It's mild, easy to lap up, and pretty appetizing to cats. It doesn't have the right balance of nutrients to be a long term solution, but right now just getting her to eat something is really important.

I don't have experience with cats in heat, I'm sorry. I'm assuming she hasn't been spayed? Is she an indoor-only cat? Have you noticed any other change in behavior, like sleeping more or playing less, not using the litter box, etc?

Try feeding her something else. I don't think RR food is very good. What about fancy feast classic chicken? Nutro natural choice sliced varieties (available at Petco), weruva, tikicat, all good choices and very enticing to picky cats. I agree that she should also be checked out by a vet if she hasn't recently, but if its clear she doesn't like her food then buy something else. 

Molly92. She plays and acts just like any other cat and she will eat some. But if my male cat comes to eat her food she backs off and doesn't eat.

Thank you I will definitely try the baby food and get her checked out