Pyramid builder short of energy food (5)
I believe the answer is:
chops
'food' is the definition.
(eg lamb chops)
'pyramid builder short of energy' is the wordplay.
'pyramid builder' becomes 'Cheops' (pharaoh who commissioned the Great Pyramid of Giza).
'short of' is a deletion indicator.
'energy' becomes 'e' (physics symbol as in E=mc2).
'cheops' with 'e' taken away is 'CHOPS'.
(Other definitions for chops that I've seen before include "Cuts of meat including part of a rib" , "Hacks" , "Axes" , "Cuts; slices of meat" , "trap" .)