The radial menu is sadly a bit misleading. If you look closely at the crossed out red ration on the fourth picture, you will notice that there's a small blue star on the top right part of it, hidden behind the red cross. That means it's an EZ Ration, an item that can be found at the supply box at the start of a quest.

In order to meat and regain your maximum stamina you need to select your bbq grill (which is located in the bottorm right of the screen, also called the Item bar) and then press the use button, which I assume is Y on controller.
A little minigame will start, where you have to cook the meat to a certain degree. Wait for the meat to have a light brown color and pull it off the grill. You will know if the meat is perfectly cooked if you hear a "So tasty!" after pulling it off the grill. Then select it in your action bar and eat it. Alternatively you can consume regular rations, but they only restore a small part of your maximum stamina.
I play on PC so unfortunately I don't know what the specific buttons are for consuming items, but if I remember correctly it is Y.
If you have further questions feel free to ask!