Can Green Tea Help You Lose Weight?

Donna Feldman, M.S., R.D.

Dieters are always searching for The Holy Grail of weight loss—a substance that melts fat effortlessly. As a result, ads for miracle pills and potions are everywhere. But it’s pretty obvious that if any of these products worked, there wouldn’t be an obesity epidemic. Recently, though, there’s evidence that a chemical found in ordinary green tea, epigallocatechin gallate, may offer a bit of weight loss magic. Since repeating that name is pretty challenging, let’s just call it EGCG for short.

Green Tea Basics
Green tea (Camellia sinensis) has been used for centuries in Asian countries. Unlike black teas, which are made with fermented leaves, green tea is produced by steaming fresh leaves. This production process results in higher content of polyphenols like EGCG, which is a flavonol. Black tea has 3-10% polyphenols, while green tea has 30-40%.

Because of its high polyphenols, green tea is ascribed all kinds of health benefits, from normalizing blood pressure to lowering cancer risk. The Natural Medicines Comprehensive Database lists many of these, but the only benefit labeled “Likely Effective” is mental alertness, likely due to the caffeine content. Future research will likely clarify whether or not any of the phenols have disease-fighting effects.

EGCG & Metabolism
The proposed mechanism for green tea’s calorie-burning properties lies in the ability of EGCG to increase thermogenesis, or heat production, by influencing enzymes in the metabolic process. This doesn’t necessarily mean that you will feel hot after drinking green tea. Rather it means that EGCG seems to increase the amount of calories burned throughout the day for all activities, from digesting food to climbing stairs to typing. Other food components, like caffeine or capsaicin (in hot peppers) can boost calorie burning, but EGCG has a stronger effect. However, the effect is not likely to melt pounds off overnight.

Research Shows Promise
A variety of studies on the effect of EGCG on weight and metabolism have been published. Most of them have encouraging results. In one study, energy expenditure was compared in men who were given green tea extract versus caffeine or plain water. The green tea extract caused a 4% boost in metabolism. 1 The amount of extract given was approximately the amount reported to be in a cup of green tea. In another example, men given tea fortified with EGCG lost more weight compared to men given unfortified tea. 2

Conclusion
If you enjoy drinking green tea and you are watching your weight, you might already be getting a small boost in metabolism. If you want to try adding green tea to your diet plan, keep in mind it also contains caffeine, albeit less than coffee. Also, the polyphenols in green tea are biologically active, and may interfere with medications you take. A pharmacist or physician can advise on this issue. As research into the effects of EGCG continues and its usefulness as a metabolism-booster is clarified, purified forms may become available. For now, enjoy a cup of green tea. Just don’t expect weight loss miracles.

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