I drink green tea, but not to lose weight. Drinking green and black teas are an integral part of my family traditions.
There are antioxidants and health benefits in numerous beverages. Frankly, drinking enough good fluids is what any of us can benefit from - ditch the sugar-laden sodas, diet and otherwise, for water (with lemon, if you need a bit of flavor).
If you want to drink 3+ cups of green tea every day, don't add sugar, lol! I can't tell you how often I see people doing that. A little honey, pure maple syrup or Stevia would be okay. But, we purists drink it "unadulterated."
Sidebar: my boss adds sweetener to his water - yikes!