Green Tea and Weight Loss – Does it Work?

In November, 2004, all of the diet forums were buzzing with news that you could lose 10 pounds in 6 weeks just by drinking green tea every day, and they’re still buzzing. This was according to Dr. Nicholas Perricone, who shared the news on the Oprah show. If you hear it on Oprah, it must be true, right? Of course this isn’t the only time we’ve heard this theory. Most dieters have seen the ads for green tea pills, diet drinks fortified with green tea, and even green tea diet patches! If you google Green tea, you’ll be quickly overwhelmed by the websites offering green tea products promising everything from effortless weight loss to fighting cancer. Is it the magic bullet you’ve been looking for, or is it too good to be true? We’re usually very skeptical of these types of claims, and we wanted to take a closer look before forming our own opinions. Hopefully what we learned will help you, too.

What is green tea? Green tea comes from the same plant as the black tea you usually drink. Green tea is prepared by picking fresh tea leaves and allowing them to dry. Black tea is prepared by fermenting the tea leaves before drying them. Catechins are flavonoids and have antioxidant properties. Tea leaves contain a catechin called epigallocatechin gallate (EGCG). Most of the catechins are destroyed when tea leaves are fermented for black tea, but are preserved in green tea. It is said that EGCG, when combined with a small amount of caffeine, causes a thermogenic effect which will boost your fat burning potential by several percentage points. You may have noticed EGCG on labels of certain diet products, such as One-a-Day Weight Smart, Metabolife, and other diet pills. Most of those products stimulants and other ingredients which may be dangerous in the long run, so they are not recommended.

Does it work? All of the weight loss claims we’ve found seem to revolve around one study that was published in 1999 by the American Journal of Clinical Nutrition. According to this study, green tea could increase energy expenditure and fat oxidation in humans by 4%. The participants consumed green tea extract three times during the course of the day (with each meal), with each dosage containing 50mg caffeine and 90mg EGCG, for a daily total of 150mg caffeine and 270mg EGCG. This would be the equivalent of about 4 cups of green tea. An increase in energy expenditure was measured at 4%.

While this may initially sound promising, let’s look at the bigger picture. First, the study was very limited because it included just 10 participants who were healthy males, were not obese, and the study lasted a short 24 hours. It is not known if the effects would be consistent if the study had last longer than 24 hours, or if the effect would taper off. It is not known what the results might be for overweight or obese women. Any long term weight loss benefit is based on theory, not results.

How much weight can you theoretically lose? Let’s say your body needs 2,000 calories to maintain your weight. If drinking 4 cups of green tea can cause a 4% increase in calories burned, then you could burn 80 extra calories per day. This amounts to around 2,400 calories per month. Since you must burn 3,500 calories to lose one pound of fat, it would take almost a year to lose 8 pounds! This is a far cry from Dr. Perricone’s promise of 10 pounds every 6 weeks. What if you drink 8 cups daily? Unfortunately, we don’t know. The study was too limited to give us much information. It is probably not likely that you would benefit much from additional dosages, and consuming too much may not be good for you.

Should you rely on green tea for weight loss? Probably not. Combined with diet and exercise, it may possibly help, but the benefit may be just a drop in the bucket for many of us. Still, green tea has many other benefits which make it worth considering. Drinking tea can still be healthy because it contains flavonoids, which are powerful antioxidants that can help protect against cancer, heart disease, and stroke. Stick with the natural cup of tea, and not the green tea products. As with many dietary supplements, you don’t always know what you are getting, and you may lose out if you go that route.

Is this Dieter’s Tea? No, Dieter’s Tea is something entirely different. This concoction is made from a variety of herbs that act as stimulant laxatives and cause diarrhea. They can cause serious side effects and should be avoided.

What about green tea pills and patches? Diet supplements are not regulated, so it’s impossible for consumers to verify what is in the pills they purchase. Also, most of the studies showing the antioxidant potential of green tea was done on the beverage, not pills. Green tea patches are a joke. As with all other diet patches, they provide no benefit and are a waste of money. Forget about them. We believe that if you want the benefits of green tea, you should just drink green tea :)

Who should not drink green tea? Avoid if you have:

  • heart problems or high blood pressure,
  • kidney disease,
  • an overactive thyroid (hyperthyroidism),
  • an anxiety or nervous disorder, or
  • a bleeding or blood clotting disorder or if you take a blood thinner such as warfarin (Coumadin).

Buying green tea: Ok, so you’ve decided to give green tea a chance to improve your health and possibly help you lose weight along with a good diet and exercise program. What should you look for, and where can you buy it? The supermarkets are filled with green tea selections these days. Many of these products may be old, having spent considerable time in a warehouse or on a shelf. The tea bags are often filled with a tea dust, and not many full, dried tea leaves. It is believed that the fresher, larger pieces contain more beneficial antioxidants, so you may want to consider a good loose tea. You can prepare it using a tea ball, instead of tea bags, or try one of the newer, fancier teapots with built in strainers. There are a wide variety of green teas available, and many come in flavors such as Cocoa Mint, Long Island Strawberry, and citrus flavored teas. You can also choose from traditional green teas with exotic names such as White Monkey, Genmai Cha, and Green Dragon.


  • Adagio Teas Delicious and fancy green teas, and a wide variety of tea accessories. They offer sample sizes of all flavors, which come in small tin boxes that fit nicely in your cupboard. This is our personal favorite tea vendor.
  • Paper Street Teas We recently discovered Paper Street Teas and are enjoying our first order from them. They offer uniquely flavored green teas which we’ve not found elsewhere. They offer sample sizes of all flavors. Unlike Adagio, though, their teas come in bags instead of tins. We’re happy with our initial purchase and plan to shop from them again.
  • Fresh Approach Diet Store offers a wide variety of green teas, oolong tea, and more. They carry Adagio brand described above, and may more top brands.
  • Read a detailed overview of green tea with benefits and precautions from the University of Maryland
  • Green tea: What it is and why it’s studied
  • Learn about green tea and cancer prevention with Dr. Ornish


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