Not everybody eats dinner every day at first, as required (6)
I believe the answer is:
needed
'required' is the definition.
(I know that required can be written as needed)
'not everybody eats dinner every day at first' is the wordplay.
'at first' indicates taking the first letters.
The initial letters of 'not everybody eats dinner every day' is 'NEEDED'.
'as' is the link.
(Other definitions for needed that I've seen before include "'Lacked, required (6)'" , "Essential; called for" , "Lacked something essential" , "Required, necessary" , "Obligatory" .)