Green Tea
Can you imagine a diet supplement that works, and is good for you, too? Well, that’s green tea. The medicinal effects of green tea have been described in Asian folklore for over 1000 years.
Green tea may work in several ways to promote weight loss. Researchers think that green tea:
- Turns on fat burning enzymes
- Decreases fat absorption in the intestines
- Inhibits fat synthesis
- Decreases insulin and blood sugar
- Decreases appetite
- Promotes thermogenesis – turning extra calories into heat
Research
A number of research studies in both humans and animals support these conclusions.
For instance, in one study, mice fed a 2% green tea powder for 16 weeks had an amazing 77% loss of visceral fat (fat around the abdomen and internal organs).
Human studies have also shown weight loss benefits due to green tea. A Japanese study divided healthy men into two groups. Each group drank one bottle of oolong tea daily for 12 weeks. Green tea extract (690 mg catechins) was added to the oolong tea of the experimental group. The control group drank plain oolong tea.
The green tea-oolong tea group lost 2.4 kg, while the control group lost 1.3 kg. The green tea-oolong tea group also showed a greater reduction in BMI, waist size, and total body fat mass compared to the oolong tea-only group. This study suggests that oolong tea is helpful for weight loss, but that green tea catechins offer further fat loss benefits.
Green tea can also improve exercise performance and endurance. Rats given green tea for 10 weeks were able to increase swimming time by 24%. However, a single “dose” of green tea was not effective. Endurance increased gradually over 10 weeks of daily intake.
Key Ingredient – EGCG
The key ingredient in green tea for weight loss seems to be EGCG, or epigallocatechin gallate. EGCG is one of several catechins found in green tea. These catechins may have health benefits far beyond weight loss. EGCG, for instance, is a powerful antioxidant.
Health Benefits Go Beyond Weight Loss
Claims have been made that green tea may lower cancer rates, decrease the incidence of heart disease and stroke, lower blood pressure, improve gum disease, decrease the risk of osteoporosis, and protect the brain against neurogenerative diseases like Parkinson’s and Alzheimers’ disease. In fact, green tea is as close to a miracle drug as we have found.
Green tea has a number of polyphenols which act as potent free radical scavengers. Just one cup of green tea provides more antioxidant power than a serving of broccoli, spinach, or strawberries.
Although the FDA continues to avow that there is not enough evidence to support health benefits due to green tea, several recently published studies in widely respected journals contradict this idea.
A 2006 article the American Journal of Clinical Nutrition reports a 50% decrease in cognitive impairment in elderly Japanese who drank more than 2 cups of green tea daily.
The Journal of the American Medical Association included a study that showed that drinking 3 or more cups of green tea per day provided a significant cardiovascular benefit.
And, according to another recent Japanese study, you may be much less likely to die – from any ailment – if you drink 5 or more cups of green tea daily.
Green Tea Has Little Caffeine
Green tea contains caffeine, about 15-20 mg in an 8 oz cup. This is significantly less than the 40-60 mg found in black tea or the 60-120 mg provided by drip coffee. Cola beverages contain 35 – 45 mg in a 12 ounce can.
Many of the weight loss effects seem to be independent of caffeine. However, one researcher suggests that the combination of EGCG and caffeine has a synergistic effect that leads to enhanced thermogeneis. This means that the combined effect is more potent than the individual effects added together.
If you need to avoid caffeine, you can still benefit from the weight loss effects of EGCG. You can take a supplement of green tea extract. Or drink decaffeinated green tea. But for best results, drink green tea that has not been decaffeinated. Or drink a cup of coffee (no sugar!) along with your EGCG supplement.
Green Tea Extract
Green tea extract may work even better than drinking a cup of green tea. Research published in the American Journal of Clinical Nutrition reports that the antioxidants in green tea extract were better absorbed than from drinking the tea. So taking a green tea extract daily might be helpful in addition to drinking green tea.
You can take advantage of both the health and weight loss benefits of green tea by making sure your daily multivitamin/mineral supplement contains EGCG.
Oolong Tea
Oolong tea (wu long tea) may also increase metabolic rate. Oolong tea contains only half as much EGCG as green tea. It is also has half the caffeine. However, it may also provide weight loss benefits.
In particular, studies have shown that oolong tea can boost thermogenesis. In fact, oolong tea may be even more effective than green tea in this respect. The thermogenic power may be due to other ingredients that have not yet been identified.
One study compared oolong tea to both green tea and water. Normal weight women drank water, oolong tea, and green tea in random order. The increase in resting energy expenditure was measured after each beverage. Drinking water led to burning an extra 2 calories in 2 hours. The green tea boosted calorie-burning by 49.5 extra calories in a 2-hour period. But drinking the oolong tea resulted in 110.7 wasted calories in the same time period, more than double the benefit of green tea.
In order to tap into the full weight loss and health benefits of these Asians teas, you may consider taking an EGCG supplement as well as drinking green or oolong tea several times per day.