Imprisoned, shedding kilo, European becomes lean (7)

I believe the answer is:

incline

'lean' is the definition.
('incline' can be a synonym of 'lean')

I can't explain the remainder of the clue.

(Other definitions for incline that I've seen before include "Gradient" , "Have tendency or slope" , "bow" , "tip" , "Lean, slope" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app