As long as you've packed the Worcestershire sauce, you can put anything in.
I'll grab some steel baskets tonight to put the food in.
Tips on what food can be cooked:
Basically any meat; lamb, beef, pork, poultry, fish. I intend to season mine for more flavour, something that can be absent in polynesian cooking
Veges: potatoes, sweet potatoes, pumpkin, carrots, any vege that cooks well when steamed.
The food can be wrapped in al-foil
One suggestion is to use aluminium food containers, with the cardboard lid, keeps everything well contained and prevents contamination from soil, ash etc.