Food is one thing after another reportedly (6)
I believe the answer is:
cereal
'food' is the definition.
(cereal is a kind of food)
'one thing after another reportedly' is the wordplay.
'one thing after another' becomes 'serial' (in a series).
'reportedly' shows a homophone (sound like).
'serial' sounds like 'CEREAL'.
'is' is the link.
(Other definitions for cereal that I've seen before include "Starchy grains used as food" , "Grain used for food" , "Breakfast food made from grain" , "Edible grain for breakfast" , "output from harvest?" .)