for things like that [drinking ice water, eating spicy food, etc] that are true, they are true to such a small degree that you'll get more benefit out of a five minute walk than whatever that thing happens to be. if you like green tea [et al], by all means drink it and be happy with your little boost. but the difference it makes is so insignificant that spending any amount of time being more active is going to do more for you.
-google first. ask questions later.