Help with constant attention meowing

I've had my Domestic Short Hair (Tortoiseshell) female for almost 7 years now and have had to deal with loud constant meowing since I got her. She was 6 months when I got her and this has been an issue ever since. She's a healthy cat that wants constant attention and food.  

She always wants food in her bowl and even when it's full she still moans for more.  Not even sure she's meowing about food but she is overweight and loves food.  

I don't know how to explain this issue cuz I know I will get comments saying all that I've already heard.

It seems like she doesn't want us (my boyfriend and I) to be sleeping and if she is awake we have to be to.  It used to be when I went to bed she would be constantly meowing and I would use ear plugs to ignore her. Then she starts again at like 3am until I get up and put more food in her bowl. Then I feed her and she continues to meow and won't let us sleep.  Nothing stops her from meowing unless I get up and stay awake.  Just the act of me sitting up in bed seems to shut her up but then I lay back down and she's at it again.

I've heard about ignoring the behaviour until it goes away but that is insanely difficult to do when you and someone else are trying to sleep.  

I don't even understand what this is all about, she's welcome to sleep on the bed and sometimes she does and some nights it's not an issue but most nights it is.  

If anyone has any advice I'm happy to hear it. 

Thanks
Rebecca

Also to be noted, she is spayed.  

Is she part siamese?  Our ragdoll is very vocal too... at least she isn't as loud as a full siamese, and she isn't monotone, sometimes she crys, sometimes she whines, somtimes she just mumbles under her breath, she warbles, chirps, she always has something to say... and if you talk back, then it turns into intent meowing.  She always acts starving too.  She is fed wet food twice a day, dry food on demand, but what she really likes to eat is temptations.  We have done pretty well teaching her not to wake us up, but if you sit up in bed even to look at the time, its on...she is convinced it must be morning and you need to get up now.

I am anxious to see what others tell you about getting a cat not to meow. 

She is not part Siamese. And I am also anxious to see if anyone has any advice.  Today is the first day I've considered giving her up.