Everybody has own system to fight insomnia.Here are some of them:
One does not eat after 18:00
Other eats something before going to bed because feels bad with the empty stomach.
Somebody tryes to avoid coffee other does not drink at all.
Most use camomile or milk or honey or mix all them in a warm sweet drink...
What scientists say about it?
I found an article that -if summarized- explains what we have to avoid and what to assume before we go to bed:
Don't eat great quantities of food, much salt and peppers (all varieties)
Don't eat anything that includes great quantities of sodium: chips and crisps, stock-cubes and any tinned food.
Don't eat chocolate and don't drink coffee, tea etc.
What CAN we eat before we go to bed?
Ant food that helps to the body to produce seratonina responsible for relaxation and psychical health.
Rise, cereals, pasta, bread, milk, vegetables and mature fruits.
The Prince of Relax is mandarine that contains many bromuri.
All this in respect of personal allergies and intollerances.