“Like all teas, oolong contains caffeine, which impacts energy metabolism by increasing our heart rate. However, studies suggest that tea consumption may also increase the breakdown of fat, independent of the effects of caffeine,” the senior study author explains. “We, therefore, wanted to examine the effects of oolong consumption versus caffeine alone on energy and fat metabolism among a group of healthy volunteers.”
All types of tea come from the same plant, but Camellia sinensis, which is the degree of oxidation, determines the variety. The chemical process is what turns the leaves black, the degree of oxidation ranges from 8-85% and determines both the taste and colour of the tea which can range from sweet to toasty, floral to grassy, and light to full-bodied. Oolong tea falls somewhere between green and black tea in terms of flavor and oxidation, and it is characterized by a unique process that includes the process of withering the plant under strong sunlight as well as oxidizing before twisting and curling.
A group of healthy participants drank either a placebo, pure caffeine, or oolong tea for a week for this study. According to the researchers, the findings showed that those drinking oolong tea or pure caffeine benefited from the increased breakdown of fat by 20% compared to the controls, and the effects of the oolong tea were noted to continue to keep working after the participants went to sleep. Neither the tea nor caffeine caused an increase in energy expenditure, and the group developed a tolerance to the caffeine present in the drinks over the study period.
As caffeine is known to affect sleep which can impact metabolism, the team also examined the participant’s quality of sleep during the study period. The researchers note that there was no difference in the sleep patterns of the placebo group or test groups, as such they believe that drinking a cup of oolong tea will not keep you awake at night, but it might help you to shed some unwanted weight.
Tokuyama concludes that “The stimulatory effects of oolong tea on fat breakdown during sleep could have real clinical relevance for controlling body weight. However, we need to determine whether the effects we observed in the 2-week study translate into actual body fat loss over a prolonged period. In addition, we want to trial a decaffeinated oolong tea to better distinguish the effects of caffeine from other components of tea, which will help us understand exactly how oolong helps with fat breakdown.”
Tea is generally considered to be healthy, especially green tea, but oolong tea has not been studied as much. Just like other teas, oolong contains vitamins, minerals, and antioxidants, along with caffeine but only about a third of the amount of caffeine that is in a cup of coffee. Drinking this tea may have benefits for your teeth, bones, heart, and brain health, but just like this study, more research is needed to draw firm conclusions.
