I worked at Cheesecake Factory for a while. Their sizes are HUGE! But part of that is because they prided themselves on not advertising in the way that places like TGI Fridays and Apple Bees does. They want people walking around malls or whatever with a cheesecake factory take out bag. So they encourage you to bring home left overs. They like the idea of free advertising via work of mouth, or by people seeing the bag.
I very rarely finish my meal when I eat there. Even their lunch portions, I will eat half for lunch, and the other half for dinner, or vice versa.