what's wrong with my CAT?

She is doing it because she can, and she is not happy with the diet.

Instead of one one bowl once a day, how about half a bowl twice a day, etc.? And I don't think I agree with simply cutting food by 50%, which is how I read going from two bowls to one bowl. Food reduction needs to be done gradually, and it will take a long time for her to lose that weight.

When she ambushes you, simply say NO, and hiss at her. Mother cats train their kittens by hissing, and even though she is more then two years old, she will know what that hiss means.

Cat lover has the best answer here so far. #1 though, make sure you have her checked out by your vet in case there's something physically wrong. If you have already done that, then here are some other options.

Cat's are creatures of habit. They also have sensitive stomachs. If you have only changed the amount you are feeding her, then make the change slowly. Like Cat Lover said, feed her twice a day, just slowly taper the amount. However, if the Vet suggested you change her food entirely, you need to make the change slowly as it can upset a cat's stomach.

If that's the case, introduce the new food along with the old food mixed, little by little until you have made a complete change over. This way the cat's stomach can get used to the new food.

As far as the behavioral issues, it could be the food issue, or it could be something else new in the environment. Have you changed your routine? Is there someone new in the house, or a new pet?

All these things can bring about this type of behavior in your otherwise docile kitty. She's trying to tell you something the only way she knows how. So be careful not to punish her, but to firmly say "No" when she's doing something she's not supposed to be doing. Also, make sure you pay close attention to when she's doing something good so you can reward her for that behavior.

When you can pinpoint the reason for the behavior, you will be able to better assess how to help your kitty return to her normal sweet self.

I doubt you would be letting her out if she was not spayed, but anyway she could be acting out with the food diet and she eats to feel content, cats are funny especially when you take them off of a schedule that they are use to, they will rebel and let you know about it, also if she is overweight I was told by my vet don't go by the instructions on the bag, every cat is different if you notice that your cat is not loosing those few pounds you may have to decrease the food a bit more, obviously you have been taking your cat to the vet so her thyroid is not a problem but with overweight cats you have to worry about diabetes which is why the vet wants your cat to loose a few pounds.

I know you may not want to hear this but it is better for your cat to be a indoor cat, I learned the hard way, my cat almost died it cost us 3,000 dollars to get him better I was told that he picked up a bacteria from some other animal that I tick or a flea had bitten him and he contracted this bacteria, I had just gotten out of the hospital from surgery and my husband woke me up in the middle of the night saying the cat was not right when I got up my cat was barely breathing with his tongue sticking out of his mouth, I flipped out and we raced him to the animal hospital, they took him right in, he was in the intensive care for 3 days, it took him over a year to get him back on his feet, never, never again will I let my cats out I never want to see my cats go through anything like that again I was devastated that I almost lost him.

she's becoming violent, mentally as well. i had a cat that was all sweet and stuff and then suddenly she was ruling the household and stealing the food off the table even though she had her own food. she sat on tables and would fight with you the whole time with her claws.we couldn't keep her anymore because she made me scared.

i think you should first see a person that studies cat behavior. maybe you can fix her behavior problems, or will have to euthanize her if she is ill mentally or else she would hurt another person. get different opinions before your final decision. i wish you luck

Only the vet will have the answer

GO TO THE VET.

get her fixed.