Green is in. And no, I’m not talking about the environment, climate change or biodegradable plastic spoons. Green Tea and green tea supplements are literally exploding in popularity all over the world. While Green Tea has always been a staple in Asian countries, its popularity has increased in the past decade almost exponentially in Western countries. Take Britain for example, between 2000-2005, sales of Green Tea had increased by 317%1 and between 2009-2011, Green Tea sales increased by £10 million, up 83%. In Australia alone, Green tea was worth about 16% of the tea market share and that was way back in 20031. So why the increase?
Green Tea Boosts Health
Green Tea has been researched for decades and a variety of beneficial effects have been shown with Green Tea consumption including benefits for conditions such as:
- Cardiovascular Disease
- Cognitive Impairment Disorders
- Oxidative Processes
But perhaps one of the biggest positives seen with increased consumption of Green Tea has been its effect on weight and fat loss. This and other reports of improved health with Green Tea consumption is what has fuelled continually increasing sales of the beverage.
Green Tea for Fat Loss
Tea has long been considered a beverage helpful in controlling body weight in Chinese culture. However, since the 1990s, when there was an increase in both sales and research of Green Tea, the use of Green Tea for weight and fat loss has increased dramatically.
Green Tea Science
So how does Green Tea affect weight loss exactly? Green Tea contains catechins; compounds known as polyphenols such as Epigallocatechin Gallate, Epicgallocatechin, Epicatechin Gallate and Epicatechin which have been shown to have several effects related to increased thermogenesis (increased metabolism through body heat production), increased fat burning or oxidation and decreased fat absorption.
For the more science based individuals, it is believed that the catechins and caffeine in Green Tea inhibits several key enzymes related to fat oxidation and energy expenditure. Catechins are known to inhibit the action of catechol o-methyltransferase and caffeine inhibits phosphodiesterase, which in turn increases the amount of noradrenaline and cyclic AMP (cAMP) circulating around the body. Both these compounds are known to help increase metabolism through thermogenesis and fat oxidation2. In addition, catechins increase the amount of hormone sensitive lipase which increases fat burning, while decreasing the activity of pancreatic and gastric lipases which decreased fat absorption3. Along with some other key reactions, it seems catechins along with caffeine have a variety of mechanisms by which is helps us to lose weight AND fat.
Green Tea & Caffeine For Weight Loss
New research4 has found that there seems to be a dose-response relationship for consumption of catechins and caffeine for thermogenesis and fat burning. In other words, the amount of catechins and caffeine you consume can be used to calculate exactly how much extra energy and fat you are burning. This can be summarised in the table below:
Per mg of Catechins
Per mg of Caffeine
For example, a standard 200mL cup of Green Tea contains 30mg of caffeine for 0.30g of fat loss and about 253mg of catechins for 5.06g of fat loss. So for every cup of Green Tea, you’re looking at almost 5.5g of fat loss. 3 cups a day and you’re looking at 5.8kg of fat loss. Of course these estimates are still quite rough due to a smaller sample size and that result would depend on a number of factors, but still, a decent result for just drinking tea.
Green Tea Extracts
Green Tea extracts are more concentrated forms of Green Tea containing a higher amount of catechins on a weight by weight basis. Generally in tablet forms, some contain as many polyphenols as 5 cups of Green Tea. While this may sound like a miracle in a tablet, it’s important not to overindulge on a good thing as there have been cases of increased oxidative damage and liver toxicity with high doses of Green Tea polyphenols. Always follow supplement instructions and if you don’t feel 100% taking the supplements, then it is best to cease consumption.
Green Tea - The Future of Good Health
Green Tea has been around for over 4000 years and its popularity has skyrocketed in the last two decades. With a whole host of benefits already known and plenty more being discovered yearly, there’s no better time to get up and make yourself a nice cup of Green Tea. After all, there must be a reason why it’s the second most consumed beverage in the world after water.
1. Australian Green Tea Growers Association. ‘Japanese Green Tea’. 2006.
2. Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P, Vandermander J. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Am J Clin Nutr 1999; 70: 1040–1045.
3. Acheson KJ, Gremaud G,Meirim I, Montigon F, Krebs Y, Fay LB, Gay LJ, Schneiter P, Schindler C, Tappy L. Metabolic effects of caffeine in humans: lipid oxidation or futile cycling? Am J ClinNutr 2004; 79: 40–46.
4. Hursel R, Viechtbauer W, Dulloo AG, Tremblay A, Tappy L, Rumpler W, Westerterp-Plantenga MS. ‘The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta-analysis.’ Obes Rev. 2011 Jul;12(7):e573-81. doi: 10.1111/j.1467-789X.2011.00862.x. Epub 2011 Mar 2.