Go to the camp manager. Ask him what needs to be done. Highlight distribute food, but don’t press enter… At the bottom of the dialogue displayed you will see
“Total faction food stock: x kcal or x day’s rations”
If this is zero, the larder is empty. Put food in the space behind the manager and select “distribute food”. The number should go up.
If it doesn’t go up, consider using debug to give yourself a hundred smoked meat or something, distribute that, and then see.
Edit: as far as I know, every job requires food for pay, it’s just not always listed. I agree it would be good if they all said it.