It's not just BA - although it might be an IAG thing. I flew IB long haul recently. We did get a lunch, although small, and after another 9 hours in flight we were quite hungry, so i went up to the galley to ask if we were going to get anymore food. We did, eventually, but it was very little. We also stepped off that plan hungry - and that was in business class.
Went straight from the airport to a restaurant for a "Pollo a la brasa"
