Think this actually makes a bit of sense from BA actually. 8.5 hours will be less than most eastbound US flights - but the vast majority of these flights are overnight anyway when passengers want to sleep (I've never understood why the ME carriers try and serve you food at 3-4am!). Going westbound, most flights bar the US/Canada NE coast will be over this threshold.
In economy, those snack boxes are absolutely awful at the end of a long haul flight; its not breakfast, its not anything.