Last-ditch opening to lose weight? No time (2-2-3)
I believe the answer is:
do-or-die
Can you help me to learn more?
(Other definitions for do-or-die that I've seen before include "Showing a determination not to compromise" , "Make a final desperate attempt to achieve" , "Involving a final desperate attempt" , "Succeed or perish" , "Make an attempt regardless of cost" .)