Gobbles suet regularly, getting very overweight (5)
I believe the answer is:
obese
'very overweight' is the definition.
(I've seen this before)
'gobbles suet regularly' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'gobbles'+'suet'='gobblessuet'
The alternate letters of 'gobblessuet' are 'OBESE'.
'getting' acts as a link.
(Other definitions for obese that I've seen before include "indecently large)" , "Very big" , "Stout" , "with a pot?" , "Grossly fat" .)