Instantiating an object by collecting a game object

Hello fellow Unity developers,

I am aiming to make a modification to the original Snake game that was seen on the old nokia phones. In my take on the game you have to acquire as much points as possible by eating healthy food and junk food. Junk food makes the snake grow and healthy food makes it smaller. So with that being the main mechanic im struggling heavily being a designer and not a programmer. I found a javascript code that sort of did what I want but i am using csharp for my project. What i want to happen is by the player clocking a piece of junk food it will instantiate a tail(cube) behind the head, and then when collecting healthy food it will remove the last tail piece. My coding skill are horrid and even if someone could start me off in the right direction im sure ill catch on fast. Thank you.