Dead lifts, personally nothing.
free weight squatting on the other hand widens my waist.
i squatted without a belt except or the last heavy set. free weight (bb)
my waist got bigger. actually my obliques got bigger
then
i started wearing the belt all the time, from the time i enter the gym, until i finish. AND i started squatting on a smith machine so my stabilizing muscles are working to the minimum.
i can till you that i noticed big difference
keep in mind i was bulking, on a normal testos dosage. both times
i agree with the squat on the smith you use less in your core so no to smith squats. i think deads to build the obliques too but some guys might not might get much growth on the obliques just genentics.
SB