I don’t know about the study, but if I go too long without coffee I turn into a psycho.
Take your canteen cup and put it on the back deck of your tank.
Take the coffee, cocoa, sugar and cream from your MRE and put them in your canteen cup.
Add a dash of 30 weight oil and a spoonful of mud or sand.
Mix with water if you have some. If not, use more oil.
You can drink it or clean your machineguns with it.