There is no such thing as a "miracle" weight loss food or drug - however there are many indications that Green Tea brings a number of benefits to those trying lose weight:
Studies have also shown green tea extracts are capable of reducing fat digestion by inhibiting digestive enzymes. Others have shown thermogenic properties of green tea (probably brought on by the interaction between its caffeine content, and catechin polyphenols)Thermogenesis is the process of the body burning fuel (fat) without making chemical energy (the calories are released as heat).
However if you are overweight or obese - and change nothing else in your life except to start drinking green tea - you are not going to have an instant weight loss miracle! But the benefits to your health are not to be sniffed at.
Combined with other weight loss techniques, Green Tea (drink or extract) is an excellent addition to your diet.