Oolong Tea for Weight Loss: Oolong tea boosts metabolism, helping you burn fat faster. Its unique catechin (an antioxidant) and caffeine combination ignites your body’s fat-burning furnace and raises your metabolism for up to 2 hours after drinking it. Oolong tea also contains polyphenols that help block fat-building enzymes. Studies have shown that drinking oolong tea has led to sustained weight loss and a smaller waist size. Be careful not to overload your tea with sugar, which will negate the benefits.