A slogan about limiting consumption, basically (2,6)
I believe the answer is:
at bottom
'basically' is the definition.
('at bottom' means basically or essentially)
'a slogan about limiting consumption' is the wordplay.
'slogan' becomes 'motto' (synonyms).
'about' says the letters should be written backwards.
'limiting' is an insertion indicator.
'consumption' becomes 'tb' (consumption is a name for TB or tuberculosis).
'motto' back-to-front is 'ottom'.
'a'+'ottom'='aottom'
'aottom' enclosing 'tb' is 'AT BOTTOM'.
(Other definitions for at bottom that I've seen before include "Basically" , "Location of 27 28" , "Like the Titanic" .)