There have been many studies on how tea can encourage weight loss—specifically green tea and oolong tea. Both green tea and oolong tea come from the same plant: Camellia sinensis. This tea plant yields four different kinds of natural teas: white tea, the tea from the newest leaves which haven’t turned green yet; green tea, the tea made from fresh tea leaves; black tea, tea from fully oxidized leaves; and oolong tea, tea made from semi-oxidized tea leaves.
Oxidation is the process of the leaf’s withering after it is plucked from the plant. Black tea is allowed to oxidize completely before the leaves are treated to high heat to stop the oxidation process. Black teas contain the highest caffeine and the least antioxidants, but they are the most popular type of tea. On the other end of the spectrum, green and white teas aren’t allowed to oxidize—they are exposed to high heat as soon as they are plucked from the tea plant. This keeps the flavor mild, the caffeine content low, and the antioxidant content high. Oolong teas, being semi-oxidized, are midway between black and green teas in caffeine and antioxidant content. That said, however, each type of tea, depending on its source, has its own balance of caffeine and antioxidant content that may vary from package to package.
There have been studies made on the effects of green tea and oolong tea on a person’s weight, as they are the teas most commonly associated to dieting.
Green tea is a rich source of polyphenol catechins. Polyphenol catechins are substances that have antioxidant and anti-inflammatory properties, and they also help speed up the metabolic process. Oolong tea is also a source of polyphenol catechins, but is more widely appreciated in China and Japan than in western countries. Nonetheless, studies on oolong tea and weight loss abound.