Sleep and Carbs
One of the reasons we can wake up during the night or early morning in particular, and struggle to get back to sleep, is because of a blood sugar drop i.e. we actually get hungry. When our blood sugar drops, the body will release adrenaline which helps mobilise stored glucose from the liver, called glycogen.
Of course, that adrenaline is not very helpful to our sleep. We then feel "wired but tired".
The currently popular low carb and intermittent fasting movements can both contribute to this issue, and many people do find sleep becomes more elusive. Yes restricting carbs can help with short term weight loss, but there is a cost, and that is stress and higher levels of adrenalin and cortisol, which eventually do damage to the metabolism.
Simple carbs are our body's preference for energy. Eating some carby food before bed (honey, potato, fruit, milk, sugar) can help with sleep. Both getting to sleep and helping sustain sleep all night.
In fact, if you wake up hungry, eating some simple carbs is the best way to calm down any sense of anxiety or adrenalin.
Hence the traditional warm milk with honey before bed. it really does help with sleep.