Increase in sweet food taken into kind of blue movie (9)
I believe the answer is:
skyrocket
'increase' is the definition.
(I know that skyrocket is a more specific form of the action increase)
'sweet food taken into kind of blue movie' is the wordplay.
'sweet food' becomes 'rock' (as in a stick of rock).
'taken into' means one lot of letters goes inside another.
'kind of blue' becomes 'sky' (sky blue).
'movie' becomes 'ET'.
'sky'+'et'='skyet'
'rock' inserted into 'skyet' is 'SKYROCKET'.
'in' is the link.
(Other definitions for skyrocket that I've seen before include "Shoot up high" , "Soar" , "Mushroom" , "Shoot up abruptly" , "Rapidly appreciate" .)