green tea and metabolism featured image

It’s no surprised that I’m geek for tea. (Yes, I just used “geek” as verb. ^_^) After participating in the IGGPPCamp Iggle Fitness Challenge (courtesy of The Mighty Jerd) and being a lover of tea, I wanted to dig deeper into what tea does to metabolism. Most studies focus on green tea. This WebMD article7 explores green tea’s impact on metabolism in humans. I was able to find the study1 the article was based on.


Epigallocatechin gallate (EGCG) is the main flavonoid that gets attention in studies and is found in higher concentrations in green and white tea compared other teas like black or oolong. This is due to the processing that occurs to create black and oolong tea6.

The study1 consisted of 10 men in their mid-20s randomly divided into three groups. They received one of three treatments in capsule form: green tea extract (50mg of caffeine and 90mg of EGCG), caffeine (50mg) or a placebo (cellulose capsule). Each man was given two capsules of the treatment three times a day. This was repeated on three different occasions. Metabolism was measured indirectly in a respiratory chamber. By measuring the amount of heat exhaled, scientists are able to examine metabolism.

Pretty cool, huh?

The results indicated that the green tea extract significantly increased metabolism by 4% compared to caffeine and the placebo. That’s a daily loss of 80 calories, assuming a 2,000 calorie diet; the equivalent to a large hard boiled egg or a small banana3.

That calorie loss does stack up to a little over 8 pounds a year. Not a bad boost!

What about teas other than green tea?

Unfortunately there aren’t many studies that compare green tea with other types of tea. Studies that I’ve found use extreme amounts of tea2 (12 cups a day) or, they steep the tea longer than typically recommended5.

I avoided studies with mice and rats.

green tea and tea pot pick me cups

Green Pekoe from Adagio Teas. Mug from Pick Me Cups.

So how much green tea should we be drinking? The EGCG content in green tea varies depending on growing conditions. The average EGCG amount in green tea is 180mg per cup4 (assuming 8 ounces per cup). Conveniently, the green tea extract in the study above contained 180mg of EGCG per day. This equals to three cups of green tea per day for a 4% increase in metabolism.

I average one cup of green tea per day; however, this study has me considering increasing my daily intake.

How about you? Is a 4% increase in metabolism enough for you to increase your green tea intake?


1Dulloo, A., Duret, C., Rohrer, D., Girardier, L., Mensi, N., Fathi, M., Chantre, P. and Vandermander, J. (1999). Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. The American Journal of Clinical Nutrition, [online] 70(6), pp.1040-1045. Available at: [Accessed 17 Sep. 2014]., (2014). Green Tea and Black Tea Metabolite Concentration Determination through Proton Nuclear Magnetic Resonance. [online] Available at: [Accessed 17 Sep. 2014].

3Live Healthy –, (2014). List of Quick & Easy 80-Calorie Snacks. [online] Available at: [Accessed 17 Sep. 2014].

4me, a. (2012). Hack Your Tea – How To Get 5 Times More Out Of A Cup Of Green Tea. [online] Acne Einstein. Available at: [Accessed 17 Sep. 2014].

5Rumpler, W., Seale, J., Clevidence, B., Judd, J., Wiley, E., Yamamoto, S., Komatsu, T., Sawaki, T., Ishikura, Y. and Hosoda, K. (2001). Oolong Tea Increases Metabolic Rate and Fat Oxidation in Men. The Journal of Nutrition, [online] 131(11), pp.2848-2852. Available at: [Accessed 10 Sep. 2014]., (2014). Tea Guardian: Polyphenols in Green & Black Teas. [online] Available at: [Accessed 17 Sep. 2014]., (2014). Green Tea Boosts Metabolism, Protects Against Diseases. [online] Available at: [Accessed 17 Sep. 2014].

8Wikipedia, (2014). Flavonoid. [online] Available at: [Accessed 17 Sep. 2014].