a friend and i (possibly 225 pounds/100kg between the 2 of us) were on an almost-empty 747 from JFK to Rome - before takeoff the flight crew asked us to move to another cabin farther back (also empty) - of course we complied, but realized after takeoff there was no way that would make a difference on a huge aircraft (i knew that even more when i got a job working operations for an airline) and they were simply playing with the 2 young (at that time at least) women on the flight - they did make us 'pizza' in their little galley oven with bread slices, ketchup packets and cream cheese - actually tasted pretty good!