Calories in, calories out.
Yes, you need a deficit for fat loss.
I would, however, if I were feeling particularly bold, advise that people do not opt for an extreme deficit, unless this is recommended by a professional who actually knows what they're doing. Even then, they would probably need strong guidance, I expect.
Current stats: age 38, height 6'2", bw ~96kg (211.6lbs)
Best lifts to date: SQ 155kg (342lbs), BP 102.5kg (226lbs), DL 220kg (485lbs), Clean & Press 70kg (154lbs) x 5