Here are some expressions that we like to use when talking about food...
Fill your boots
I love this expression because you can almost imagine literally filling your boots with your favourite stew...
It really means to have as much of something as you want, to do something to the full. You can use this expression of many other things too, not just food.
Fran and Paul are at a buffet, Fran can't believe how much food there is!
Fran: "I'm so hungry shall we tuck in?"
Paul: "Go on Fran, fill your boots!"
Here are some expression that mention food, but they don't refer to it...
A piece of cake: (Easy) This report was a piece of cake!
Spill the beans: (Tell a secret) I'll tried not to spill the beans, but I couldn't help it! Sorry.
Small potatoes: (unimportant) We don't need to worry about those people, they are small potatoes.
Sugar coat it: Gloss over bad information. Please tell me the whole truth and don't sugar coat it.
Go bananas: To go crazy. Make sure you tidy your room, your mum is gonna go bananas when she sees this mess!
Do you know any other expression related to food?
Why don't you share your favourites with us?
Could you share some expression with us in your language?
tuck in; (phrasal verb) eat heartily, devour, consume, to gobble up.
gloss over; (phrasal verb) to cover up something.