Green tea is one of those things that's really healthy for you, but its health benefits have been greatly exaggerated; one of the things which has been consistently reported about green tea is that it helps you lose weight, but scientists didn't know how (or if) this happens. Now, a team from Poland believe they've zeroed in on this mystery: it's all about the starch.
Jaroslaw Walkowiak of Poznan University of Medical Sciences, Poland, found that a single dose of green tea extract made people digest less starch and eliminate more of it. He gave people the equivalent of drinking a few cups of green tea every day after they had breakfast.
"Green tea is known worldwide for its beneficial effects on human health," the researchers write in the journal Scientific Reports. "However, objective data evaluating this influence in humans is scarce."
Indeed, green tea is given credit for many health benefits - it's supposed to help against cancer, but despite suggestive evidence, there is no conclusive evidence that green tea helps to prevent or treat cancer. It's supposed to level glycemic control but again, evidence is inconclusive, and it's supposed to help with losing weight. It's safe to say that green tea is quite controversial, but hopefully, studies like this one will shed some light on what the substance actually does.
"In most subjects (78.6%), the decreased starch digestion and absorption due to GTE was rapid and the aforesaid effect persisted until the last measure."
They continue making a case for using the substance instead of other weight-loss substances.
"Our data suggest that the use of GTE is a viable alternative to pharmaceutical inhibitors of glucoside hydrolase enzymes. This plant extract is widely available, inexpensive, and well tolerated, so it has potential utility for weight control and the treatment of diabetes. Our study supports the concept that pure GTE inhibits starch digestion and absorption. However, the clinical significance of each green tea catechin and the exact mechanism responsible for this action in humans remain to be determined."
The debate around green tea won't end anytime soon, but regarding weight loss, the evidence seems to be piling up: a few cups of green tea per day might actually help you lose weight.
Journal Reference: Klaudia Lochocka, Joanna Bajerska, Aleksandra Glapa, Ewa Fidler-Witon, Jan K. Nowak, Tomasz Szczapa, Philip Grebowiec, Aleksandra Lisowska & Jaroslaw Walkowiak. Green tea extract decreases starch digestion and absorption from a test meal in humans: a randomized, placebo-controlled crossover study. doi:10.1038/srep12015