Pass on first of tips in attempt to lose weight (4)
I believe the answer is:
diet
'attempt to lose weight' is the definition.
'pass on first of tips' is the wordplay.
'pass' becomes 'die' (I've seen this before).
'on' is a charade indicator (letters next to each other).
'first of tips' becomes 't' (dst letter of 'tips').
'die'+'t'='DIET'
'in' acts as a link.
(Other definitions for diet that I've seen before include "control weight" , "Special food regime" , "Legislative assembly in some countries" , "go without sugar perhaps" , "Regimen for eating" .)