First you are going to have to leave extra food out. Leave dry cat food. Most cats will not eat to excess and become obese unless you are feeding them really yummy table type food ( think tuna, chicken from the grocer etc).
When and if that doesn't get them to stop nagging you, you will have to learn to ignore them, until they stop. Cats know exactly how to manipulate you to get your attention, and get you to do what they want. My cats would yowl until I got out of the shower. The only solution was to leave the bathroom door open.
In the case of the bedroom, they would yowl because I refused to have them in the bedroom, because they will play all night on my bed.
They yowled for ages, and it was hard to sleep. I had to get ear plus, but eventually, when I didn't cave they realized the yowling was useless and stopped.
You will have to live through it for a while and ignore them.
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