According to some celebrity endorsements, the easy way to get rid of that middle-aged spread it to sit back and enjoy a nice cup of tea. Given that we Brits drink around 165 million cups of tea every day (or 60 billion a year) we should be among the slimmer countries in the world rather than one of the fattest. So this looks like another good example of the general principle that if it seems too good to be true, it probably is.
The tea that is usually being referred to in the context of weight loss isn’t the standard British brew (black teas), but much more exotic leaves, especially green tea. Both green and black teas come from the same plant – Camelia sinensis – but the leaves are processed differently. As a result green tea contains a group of flavonoids called catechins, the most abundant of which is epigallatocatechin gallate (EGCG). Together with caffeine, which is found in both green and black tea, it is the activity of catechins – particularly EGCG – which is responsible for weight loss. Is this just wishful thinking?
EGCG and other catechins are said to be “fat burners” i.e. they promote the breakdown (oxidation) of fats leading to weight loss. Several studies have shown that green tea does indeed increase fat oxidation at rest, by up to 16%. With regard to weight loss, a recent analysis of 11 different studies showed that subjects who drank green tea lost – on average – 1.3kg more weight over a 12-week period than those in the control group. This is a significant, though admittedly rather a modest effect. Furthermore, the sceptic might argue that this sort of weight loss could be achieved simply by switching from a milky, sugary cup of black tea to a cup of calorie-free green tea. A standard cup of tea with milk and one sugar has around 40 cals, so assuming you drink 4 cups each day, over a 12-week period this would amount to a saving of 13440 calories. This equates to a 3.8lbs (1.7kg) weight loss which is actually slightly more than the 1.3kg (2.9lbs) attributed to green tea in the study referred to above.
So whether or not green tea has specific fat-burning properties to aid weight loss, if you are a regular black tea (or coffee) drinker with milk and sugar, switching to zero calorie green (or other tea) could be a good idea for weight loss. And the bonus is that digestive biscuits don’t taste anything like as nice with green tea.
Dr David Ashton MD PhD
18th May 2012