We'll facts, stats, and figures aside...
my experience with coming down and experimenting with supposed "tryptophan(& tryptophan related substance) containing" consumables, is that Bananas most certainly DO have a profoundly noticable effect on a 'post 20-48hour' comedown.
I live 20mins from a train station and have found myself very very strung out on occasion at the thought of having to travel to the city for any reason during these "dont touch me until ive had my espresso or I'll rip your holy head off" periods... and I use the word, 'period' very concisely.
Time and time again I get myself a funky ripe banana (believe it or not, there are funky ones out there..), whack some cheap vanilla icecream and some FULL FAT milk in a blender with it, and down the lot before I set off. On each occasion it has usually altered my mood dramatically by the time I set foot on the train. You may argue that it is psychological but I'm way too aware of my emotional make up and the things I do to it to believe that... ...the changes are quite good I find...
The thing is.. I HATE bananas when im in a normal frame of mind... but post-MDMA there is a certain 'appeal' to them that must indicate some kind of "I need to eat that" chemical association attraction. (In much the same way that a large number of pregnant women experience a craving for grapefruit, then later find out that they have abnormally low blood pressure and that grapefruit is a very very versatile means of raising their blood pressure).. *cue twilight zone music*
In future I can say with most cetainty that "at least I know whats in my fruit and that it may not be imported but I know for sure that the come up time is about 20mins",
hmm... another mood altering substance enters the ranks for classification... "MAKE THOSE BODIES SING!"