body parts
food
animals
100

to pick one's brain

ask for information about something

100

have a sweet tooth

like sweet food

100

to feel like a fish out of water

to feel uncomfortable

200

the cold shoulder

to be unfriendly on purpose 

200

to pig out

to eat a lot of food

200

The cat's out of the bag

to tell a secret

300

pull one's leg

play a trick on someone

300

to have eyes bigger than one's stomach

to want to eat more food that you can

300

to kill two birds with the one stone

to do two things at once

400

go over my head

beyond my ability

400

to bite ones tongue

to stop yourself from saying something

400

an early bird

like to get up early

500

get it off my chest

say something that has been bothering me

500

to eat one's words

to take back something you said

500

the elephant in the room

an issue that no one wants to talk about