Full of calories (9)
(Another definition for fattening that I've seen is " of high-calorie food?".)
'full of calories' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rich that I've seen before include "productive" , "Affluent" , "(Person) with plenty of money" , "very funny?" , "Of great worth or quality" .)