The Science Behind The Tea
If you look at the ingredients list for any fat burning supplement, chances are that green tea will be on there. This is because green tea has been shown to increase fat burning and boost the metabolic rate, in human controlled trials (1, 2).
In one study in 10 healthy men, green tea increased energy expenditure by 4% (3). Another study showed that fat oxidation was increased by 17%, indicating that green tea may selectively increase the burning of fat (4).
Caffeine itself has also been shown to improve physical performance by mobilizing fatty acids from the fat tissues and making them available for use as energy (5, 6). In two separate review studies, caffeine has been shown to increase physical performance by 11-12%, on average (7, 8).
1. 'Obesity and thermogenesis related to the consumption of caffeine, ephedrine, capsaicin, and green tea'2. 'Effects of encapsulated green tea and Guarana extracts containing a mixture of epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men.'
'Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans.'
Department of Physiology, Faculty of Medicine, University of Geneva. December 1999
Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans'
Human Performance Laboratory The University of Birmingham, United Kingdom. March 2008
5. 'Caffeine and sports activity: a review.'
Faculté de Médecine, Nancy, France. July 1994
6. 'Effects of caffeine ingestion on metabolism and exercise performance.'
Costill DL. January 1978
7. 'Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta-analysis.' University of Luton, United Kingdom. Effects of caffeine ingestion on exercise testing: a meta-analysis.' University of Luton, United Kingdom. December 2004