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Sipping a cool glass of iced tea feels so refreshing and hydrating! Wouldn’t it be even better if you knew that doing so might also help your waistline? We wanted to find out if that was the case, so we explored which type of iced tea (black, green or white) has a waist-slimming effect.
True tea is brewed from the leaves of the camellia sinensis plant. The names of the tea colors have to do with leaf maturity and extent of oxidation. Oxidation is the process responsible for the browning of black tea leaves, as well as the development of new flavonoids. When the leaves are simply steamed and crushed manually without additional oxidation they retain a green color. White tea is the variant that undergoes the least processing and the leaves are harvested while the tea plant is still young.
Here’s how the three types fare in comparison to one another for belly fat reduction:
Black tea* is high in polyphenols called flavonoids. A predominant form of flavonoids are polyphenolic catechins. The process of oxidation browns the leaves and causes reduced catechin content – by around 85% compared to green tea – and less bitterness.1
One study on black tea consumption (3 cups/day) showed positive effects on weight and waist circumference at 3 months, but not at 6 months.2 Animal and small human studies suggest that the caffeine in black tea may increase basal metabolism by up to 6 percent.3 It’s proposed that caffeine encourages the body to breakdown stored fat and stimulate its metabolism. With caffeine, more is not better! Safety guidelines recommend you should only consume up to 400mg of caffeine per day (equal to 5-8 cups of black tea). Also, note that black tea is a rich source of oxalates which can cause kidney stones.
* Chinese black tea (called red tea in China since brewing causes a reddish color) is not the same: The leaves are aged for a very long time giving Chinese black tea a different flavor and flavonoid profile. Oolong tea is made from sun-dried tea leaves that are partially oxidized. Pu’er tea is made from leaves that have been oxidized then microbially fermented.
Green tea is characteristically bitter and astringent and has the most catechins compared to black tea. There are eight prominent catechins found in green tea including epigallocatechin gallate (EGCG) which is believed to be the most pharmacologically active and is the most extensively studied. Green tea catechins (predominantly EGCG) may influence fat distribution by preventing fat cell proliferation, reducing fat absorption, increasing energy expenditure and increasing fat burning.4
It appears that catechins’ ability to impact abdominal fat takes place at a certain threshold. It takes about 500mg catechins (equal to 5 cups of green tea)4,5 to modestly reduce abdominal fat or waist circumference, based on studies using catechin-enhanced beverages.6,7 Again, more is not better… consuming greater than 800mg of EGCG in one sitting would be like slamming a gallon of green tea all at once, and instead of acting as an antioxidant (as it does at lower levels), you’d get pro-oxidant effects!
Aside from sympathetic nervous system action, green tea catechins may also increase satiety. Green tea catechins increase the release of hormones that reduce our appetite and induce a satiating effect, telling our brain that we’ve eaten enough.8
The caffeine naturally present in green tea may increase energy expenditure on its own but it’s evident that caffeine works synergistically with the catechins. A meta-analysis of research4 and other long-term studies9 indicate that decaffeinated green tea extracts do not have an effect on body weight or abdominal fat.
White tea offers a sweeter and lighter taste than black or green teas although it still contains a variety of compounds including EGCG. One study showed that the range of its total catechin content can overlap the variance found in green tea, making the amount comparable.10 The authors concluded that the source, cultivation, and processing of a given tea may have more influence on catechin content than whether it is green or white.10 Another study demonstrated that the caffeine content between green and white tea is not appreciably different.11
Human studies investigating white tea’s effects on abdominal fat are rare. Results of an in vitro study indicated that white tea extract effectively reduced fat deposition and promoted the breakdown of fat.12
The winner… ICED GREEN TEA, if you drink enough – 5 cups! For higher effectiveness, consume green tea while fasted – making it your first food of the day to increase absorption of catechins4 – and spread remaining intake throughout the day rather than all at once.
Tips on tea preparation before you ice it:
- Check bottled tea labels and choose only pure, unadulterated tea—or save money and brew your own at home.
- For the most catechins, look for quality packaging to ensure better storage with minimal exposure to oxygen, light, and moisture.
- Use bottled or deionized water to extract (nearly double) more catechins when brewing tea.13 Steeping leaves in tap water, especially ‘hard water’ high in minerals, leads to a less bitter but also less potent tea.15
- The ideal water temperature and steep time for maximum extraction vary by tea type. For example, brew white tea bags at 98°C [208°F] for 7 minutes to obtain the highest polyphenol content and pleasant taste.14
- Consider adding lemon or creamer/milk to allow more catechins to be absorbed since they stabilize tea polyphenols in the intestine, inhibiting their degradation from an alkaline pH.15