The hyperbole about the Dreamliner using advanced composite materials making it lighter is not made out in the facts.
The most comparable Boeing aircraft to the Dreamliner 787-900 is the 767-400. The former being a little wider with longer wings and a touch shorter. The extensive use of composites suggest then that the aircraft should be significantly lighter
However using the Operating Empty Weight metric (akin to Tare weight), the 787-900 is about 25000kg heavier than the 767-400.
Richard Guest CNN “cash for comment “ said that the airline uses special streamlined and lighter cutlery to maximise mission range - the wine glass without the stem helps get the aircraft to LHR. It’s akin to the Olive myth which suggested an airline found that removing olives from the menu resulted in significant fuel saving.
It’s also 3000kg heavier than the A330-300 (these 2 share similar cabin floor area)
The 787-900 carry more fuel - 27000kg more than the 767-400
(Data using Wikipedia- which is as accurate as...)