There are supposedly no shortcuts when it comes to losing weight, but that may soon change. Researchers from the University of Tsukuba in Japan have discovered that drinking two cups of oolong tea on a daily basis can jumpstart the breakdown of fat while sleeping.
In comparison to a placebo group, participants drinking oolong tea every day saw their nightly levels of fat breakdown increase by 20%.
Like a middle child vying for mom and dad’s attention, oolong tea isn’t nearly as popular or well known as other varieties of tea like black or green. All types of tea originate from the same plant (Camellia sinensis), with the degree of tea leaf oxidation determining the specific varieties.
Oxidation refers to the chemical reaction that turns tea leaves black. So, black tea is fully oxidized and features a distinct “tea taste,” while green tea is totally unoxidized and mild in flavor. Oolong tea falls in the middle of this oxidation spectrum; it is partially oxidized with a mild tea taste.
Study authors say that while the benefits of green or black tea are well established and frequently discussed, what oolong tea can bring to the table has largely remained a mystery.
“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,” explains senior study author Professor Kumpei Tokuyama. “We therefore wanted to examine the effects of oolong consumption versus caffeine alone on energy and fat metabolism among a group of healthy volunteers.”
Both oolong tea and pure caffeine resulted in a 20% increase in fat breakdown among study participants over two weeks, but the oolong tea’s fat-burning benefits actually kept working while subjects slept.
It’s also important to note that regular oolong tea consumption didn’t lead to an uptick in “energy expenditure” among participants. This suggests that subjects’ bodies acclimated quickly to the extra caffeine in the tea, and developed a tolerance to its stimulating effects. That’s an important note considering oolong tea can’t help anyone lose weight while they sleep if it also keeps them awake all night.
On a related note, drinking oolong tea every day didn’t have any impact whatsoever on subjects’ sleep patterns. There was no difference in sleep quality and the amount of time it took subjects to fall asleep between the oolong tea group and the placebo group. In short, oolong tea will not impede a restful night’s sleep at all.
As is the case with so many scientific studies, study authors caution that no concrete conclusions can be drawn just yet regarding oolong tea and sustained lasting weight loss. Longer, more detailed future studies must take place before that can happen.
“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,” Professor Tokuyama concludes.
The full study can be found here, published in Nutrients.