just a rough estimate,allowing for washing
in salt water
with a fresh water rinse. and includes water for cooking
if on a long passage
would normally double those quantaties to build in a 100% safety
also tend to bulk buy staples like rice,pasta,instant potatoe,couscous,milk powder,stock cubes,tinned tomatoes etc and store in air tight containers which will store for 12 months plus,for my own boat.
though on short deliveries i try to be more economical,but you will allways find needy livaboards at the other end who will dispose of any unused stuff!!!!!!