Listen it depends not only on brand of tea but also how it is made. I am against promoting any brand. But open leaves green tea is always a better option. You can always add mint leaves, small ginger piece and lemon grass. You can take it any time but make sure if you are taking any tea after meals. Give a gap of at least 1 hour, and not before bed. It is also good if you can manage to take it 5 times a day (to reduce weight) or else 2 times a day will also do.