Slimming plan (4)
I believe the answer is:
diet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">slimming plan</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for diet that I've seen before include "Range of food eaten" , "Restricted cheer" , "regular intake" , "Food plan" , "International conference" .)