Do cats meow louder when they’re hungry ?

They do when they are really trying to get your attention and you are not listening. 

Sometimes Lilac and Dildy will scream REALLY loud when they're hungry. I thought I read somewhere that the hunger chemicals make their vocal chords tighter.

My family cat never meowed. When he was hungry, he looked at me, and then he looked at the box of dry cat food on top of the refrigerator and he got food.  When he wanted to go to the back yard, he looked at me and then looked at the door. If I wouldn't open the door, then he jumped up and grabbed the door knob with both of his front paws. 

Heck mine always have food and they love to meow LOUD!!!! One time they ate all the food, and they meowed the same! They are Siamese so very chatty in the beginning!

Cats are such individualists that I hate giving broad responses, but yes, they do get louder.  A solid black named Boston that I feed gets very loud (and bossy).  OTOH Piewackit just stares at me until food appears, at which I am ignored.

Yes, they want it to be known they're hungry!

I think so. Every morning, my cat jumps on my bed and meows at me in front of my face when he wants to be fed. 

Mine just acts like she loves me. Just before she lays down a 5 inch puke tube o meow mix she goes...blurtch..blaaiiket.

MEOW MEOW MEOW

No, they get louder to get your attention.

Yes.  Sometimes it creat fear. 

My cat has two distinct meows, one is “feed me” and the other is “ I’ve brought you a little present”.
He doesn’t get louder when hungry but just stares at you until you go and get the food.

One of my adult cats does meow louder when she wants food, a water refill, cuddles, or is scared of something. My other cat meows loudly when he is upset by something. Currently he is sick, so he has been doing that a lot. Based on my only examples, I would say they do meow louder if they are hungry and want food.
If your cat has enough accesible food and water and is meowing loudly, I suggest that you give them attention to make sure they feel okay. Petting and playing with them helps and sometimes they might just want to be in the same room as you.

One of ours does.  To start with she'll come and stare at you (you're supposed to notice), if that doesn't work she'll call softly, and if THAT doesn't work she'll downright yell.

yes because my dog likes to go to his gate when he's hungry

Yes, and it is scandalous.