It is quite common in thematic puzzles, elliemay, where a number of clues have no definition and the answers are in some way related to the theme. In this puzzle there are in fact three 'gimmicks' - some clues have an extra letter in the clue, some clues lead to the answer plus an extra letter (these extra letters in clue order tell us something about the theme) and some these two types of clue also have no definition. Quite a bit to grasp if you are not used to doing them but food and drink to 'themed addicts'!