Am in east, after start of feast, where there's a shortage of food (6)
I believe the answer is:
famine
'there's a shortage of food' is the definition.
(I've seen this before)
'am in east after start of feast' is the wordplay.
'east' becomes 'e' ('E' can be a synonym of 'east').
'after' says to put letters next to each other.
'start of' suggests taking the first letters.
The initial letter of 'feast' is 'f'.
'am'+'in'+'e'='amine'
'amine' after 'f' is 'FAMINE'.
'where' acts as a link.
(Other definitions for famine that I've seen before include "Extreme lack of food" , "Extreme shortage of food" , "Widespread scarcity of food" , "A great shortage as of food" , "Hunger" .)