But the long term effects are observable as well, aren't they? I understand where you're coming from, and I'm not too excited when people pipe up with things l

But the long term effects are observable as well, aren't they? I understand where you're coming from, and I'm not too excited when people pipe up with things like "the brain is just like X, so you just need to eat more Y to fix your Z", but we're learning plenty of things about how the brain works, and I believe that we do so because we consider it as a complex system that is not unlike a machine. Remove its fuel, and it will stop operating shortly, cut away parts of it and you'll see functionality change or being lost. I see no harm in reasoning about it as a very complex and very large machine with tons of inputs, outputs and modification systems. A long time ago, we'd consider the heart a mystery full of magic, and now we're regularly transplanting hearts and I believe we're "within reach" (though rather decades than months) of implanting completely artificial hearts. I see no reason why we shouldn't make progress towards a better understanding of the brain in the same way.