Thigh affected by each meal (4,3)
I believe the answer is:
high tea
'meal' is the definition.
(I know that high tea is a type of dinner)
'thigh affected by each' is the wordplay.
'affected' indicates an anagram.
'by' says to put letters next to each other.
'each' becomes 'ea' (abbreviation).
'thigh' is an anagram of 'hight'.
'hight'+'ea'='HIGH TEA'
(Other definitions for high tea that I've seen before include "A lofty kind of evening meal" , "Late afternoon meal which includes a cooked dish" , "Early evening meal" , "Early-evening meal" , "Late-afternoon meal" .)