Okay, if your table is on another sheet, you will need to use a named range to do a dropdown. Very easy - just go to the sheet, select all of the names (eg A1:A30), then click into the Name Box (just above the A column header) and type Food (or whatever other name you want).
Then, click into your other sheet, and select cell A1 (or wherever you want the dropdown). Then go to the Data menu and select Validation. In the Allow box select List and in the Source box type =Food.
Et voila, a dropdown list!
You can't type in a one-off with a drop down list - but your VLOOKUP wouldn't work anyway if the value wasn't in the table. If you think you may want to add things to your table (and your dropdown), then just leave some blank lines at the bottom of the range that you use for the VLOOKUP and the same number of blank lines when you set up your named range.
(You can also create dynamic named ranges, that change size automatically when you add more data, but that's probably overkill here! If you want to know how to do it, do a quick search for dynamic range at mrexcel.com, or PM me there - same username).