I’ve not come across research about this, but my guess is it’s part of our circadian rhythm: waking at first light, working through the day, and then preparing ourselves for our next sleep. It makes sense that we see the time after the evening meal as the time for us to unwind, time for relaxation and recreation. It’s when we would have sat around the fire, telling stories. It’s important for our biology for us to go to bed as relaxed as possible, as we’ll get a deeper and longer sleep.
That inherent need to unwind is the cue, and what got easily conditioned to it is some highly addictive, modern, manufactured and processed food, which often includes sugar. And, of course, alcohol, TV… whatever.
Alongside and together with this, addictive desire right at the end of a meal can be a direct result of the pleasure you got from that meal. You enjoyed it so much, you want more of it! Of course you do! That’s why some of the “old timers” in OA advise only eating bland food. I find that useful to remember; when I want more I think: I really enjoyed that, didn’t I?