Brian0787 wrote:
Maybe the sugar ends up spiking and then a kind of crash comes after.
It seems there's some truth in that.
Also tryptophan can increase serotonin and melatonin, and carbohydrates can push them into your brain. That could all make you sleepy, if there's such a thing as junk food that contains tryptophan. And pigging out can cause drowsiness because the blood gets diverted to the digestive system.
I don't eat unhealthy food, but I can find it harder to sleep if I'm a bit hungry. Contrary to the common advice, I'm better off eating just before bedtime, though I try to avoid fat in case it gives me heartburn.