The Engineered Garments Oxford Pant is a BIG pant—both in size and stature. Built off a super relaxed, wide-legged pattern they surely use twice the amount of cloth of a normal pair of trousers.
There's so much fabric here you'd be able to make a set of curtains out of them. A good bunch of that cloth is taken-in by the generous double-pleated front which allows plenty of volume to be gathered before the waist. The pleats also allow fabric to cinch more cleanly if you're pulling the hidden drawstrings tight to get a better fit.