What are the best ways to fall back asleep after awakening?

Every night or every other night, when I wake up to use the restroom around 3 am or so, I can’t fall back asleep for at least another hour! It sucks. If I drink hot chocolate, it will help and I will fall asleep, but I’m on a strict diet and have been for a year, I don’t want to have to drink hot chocolate every night.

So what would you say are the best ways I can fall back asleep fast!? I am 19 and male.

And yes i’ve already thought of not drinking water before bed so I don’t wake up, but before I use to wake up 3 to 4 times, now I have minimized it to 1, I can’t get any better than that, trust me. Not unless I want to die of dehydration. Thank you for all answers!