Weight loss and green tea: stirring the (tea) pot

Green Tea: Viable alternative to ephedra?

One botanical that may be a viable alternative to ephedra is green tea. As both a properly brewed beverage and dietary supplement extract form, green tea contains a cocktail of bioactives, a virtual 5-piece metabolic band.

First, it contains caffeine, the companion bioactive in virtually all ephedra-containing products (usually provided from extracts of Kola Nut, Guarana, or even Yerba Mate).

Secondly, green tea has a host of four prominent catechins (CAT-u-kins), astringent, mouth-"drying" constituents that possess a number of metabolic and physiological tricks up their sleeves. The King of Catechins is EGCG (EpiGalloCatechin Gallate), which also happens to occur in the greatest amount among the green tea catechins.

One-day study shows it burns extra calories even without exercise

What got the water boiling on green tea and body composition was a paper published 3 years ago. In it, ten lean to slightly overweight young male subjects (who consumed an average range of 100-200 mg of caffeine/day, equal to about 1-2 cups of moderate-strength coffee) were given at three separate times three different formulations: (1) two capsules of a green tea extract supplying 50 mg of caffeine and 90 mg of EGCG, (2) two caps containing 50 mg of caffeine, or (3) two caps containing cellulose.

These men took each of the two caps three times (with meals) over one day while they "lived" in a metabolic chamber for 24 hours straight. These very expensive "calorie crypts" allow researchers to directly and precisely measure the number and type of calories burned. Each treatment was separated by 5-10 days.

When they took the green tea extract, total calories burned were 2.8% (266) and 3.5% (329) higher (over 24 hours), relative to the placebo and caffeine caps, respectively. Moreover, the green tea caps appeared to shift the fuel of choice away from carbs and more toward fats.

12-week study shows weight loss with green tea

The immediate assumption: weight and fat loss! But for thermogenics to "work," meaning an increased rate of weight and fat loss, the effects have to be sustained over a period of weeks to months. A one-hit band is very different than one with a string of gold and platinum records.

Additional calories burned daily taking green tea (90mg EGCG) and 50mg of caffeine 3 times daily without exerciseA research study published this year followed 70 overweight/overfat subjects (63 women and 7 men) for a period of 12 weeks while they took the same green tea extract and dose, yet this time only at morning and mid-day periods (total intake of 150 mg of caffeine and 270 mg of EGCG/day). This study did not have a placebo group. A total of 66 subjects completed the 12-week journey, with the average weight loss being 7.7 pounds (3 pounds were lost by week 4) and a 4 cm drop in waist size (2 cm at week 4). Blood pressure also fell as the study progressed.

Could an adequate dose of caffeine and catechins from green tea successfully pinch hit for ephedra + caffeine? A placebo/caffeine-controlled study would help answer the question.

Weight loss in 12 weeks taking green tea (135mg of EGCG) and 75mg of caffeine twice daily

Test-tube study shows green tea inhibits fat digestion

A different study revealed a novel way in which green tea extracts could promote weight and fat loss: inhibition of fat digestion. These researchers found the same green tea extract (used in the 12-week study above) to reduce the amount of fat digested in a test tube. This 'out of body' result is qualitatively similar to that seen with some chitosan ingredients and the prescription drug Xenical.

In addition to its in vitro fat digestion-arresting effects, green tea catechins may also reduce the absorption of carbohydrates and have favorable effects upon carbohydrate metabolism by "mimicking" some of the effects of insulin.

How to consume green tea

A suitable way of obtaining green tea catechins and its tag along caffeine is selecting a supplement where the amount of caffeine and catechins (derived from a green tea extract) are disclosed on the label. An effective complement to a green tea extract-containing supplement is to drink freshly brewed hot or iced green tea, which will be steeped in catechins. Most "ready-to-drink" green tea beverages likely have trivial amounts of catechins and caffeine, unless caffeine is added from another source.

Selected Sources

  • Dulloo AG, et al. Efficacy of a green tea extract rich in catechin polyphenois and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Am J Clin Nutr 1999;70:1040-5.
  • Chantre P and Lairon D. Recent findings of green tea extract AR25 (Exolise) and its activity for the treatment of obesity. Phytomedicine 2002;9:3-8.
  • Juhel C, et al. Green tea extract (AR25) inhibits lipolysis of triglycerides in gastric and duodenal medium in vitro. J Nutr Biochem 2000;11:45-51.
  • Kobayashi Y, et al. Green tea polyphenois inhibit the sodium-dependent glucose transfer of intestinal epithelial cells by a competitive mechanism. J Agrid Fd Chem 2000;48:5618-23.
  • Anderson RA and Polansky MM. Tea enhances insulin activity. J Agric Fd Chem 2002;50:7182-6.
  • Waltner-Law ME, et al. Epigallocatechin gallate, a constituent of green tea, represses hepatic glucose production. J Biol Chem 2002;277:34933-40.

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