Pre-marathon meal (5)
I believe the answer is:
pasta
'pre-marathon meal' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pasta that I've seen before include "Flour and water foodstuff" , "Italian foodstuff" , "Spaghetti, orzo etc" , "Processed flour dough" , "Fusilli, conchiglie and penne" .)