Of course it's impossible for one person's evidence to refute what happens "in general", but either this isn't true for me, or I don't understand what you mean. I love broccoli. I don't hate ice cream, but I certainly wouldn't eat it every day, which I'd be happy to do for broccoli. I don't think I'm responding in any significant way to external factors, only to eating one regularly making me feel better than eating the other regularly. I don't imagine my experience to be universal, but nor do I imagine it to be very rare.
However, I addressed your point:
> obesity rates would show that nothing really changes, in how much they "like" things.
If everyone loved healthy food and hated treats, obesity rates wouldn't be so high, and Frito-Lay wouldn't be one of the most profitable food companies in the world. Obviously, no general claim is universal.