Research and Scientific Publication

Green tea increases energy expenditure

Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans

By Abdul G Dulloo, Claudette Duret, Dorothee Rohrer, Lucien Girardier, Nouri Mensi, Marc Fathi, Philippe Chantre, and Jacques Vandermander
Published in American Journal of Clinical Nutrition1999;70:1040–5



The researchers note that, “Fundamentally, there are only two ways to treat obesity: reduce energy intake or increase energy expenditure.”

They then suggest that “because thermogenesis and fat oxidation are to a large extent under the control of the sympathetic nervous system, approaches that mimic or interfere with the sympathetic nervous system and its neurotransmitter norepinephrine offer a rational approach for obesity management.”

The researchers compared energy output over 24 hours for men in three groups (green tea extract, caffeine, placebo). Subjects were randomly assigned across groups and in different groups.


When the men were in the green tea extract group there was a significant increase in their 24 hour energy expenditure.


The researchers concluded that green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se.

The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis, fat oxidation, or both.