Drinking green tea is a healthy way to ease your weight loss. However, if adding green tea to your diet is the only modification in your life style, your weight loss is going to be rather slow.
Active Components of Green Tea
Green tea contains caffeine and flavonoids. Epigallocatechin is the most recognized flavonoid that has beneficial effects on weight loss and other aspects of your health, including insulin sensitivity and lipid profile. The amounts of these components and their ratio dramatically vary between different kinds of green tea or tea extracts. To compare the effects of tea that you drink with the effects described in research studies, you may need to find the information about the content of these ingredients in your tea. Green tea is a safe supplement. However, if you are taking any medications, consult your doctor. Also, tea extracts should not be used in doses that significantly exceed those described below, since some research has shown severe liver damage with weight loss products containing green tea.
Thermogenic Effect of Green Tea
If you want to lose one pound of your weight, you need to create a deficit between your energy intake and energy expenditure that equals 3,500 calories. The healthy speed of creating this deficit is 500 calories per day or less. The next question is how much green tea you need to ingest to reach this number of calories. Dr. Abdul Duloo, an expert in nutritional energetics at the University of Fribourg in Switzerland, investigated the effect of green tea on energy expenditure. He and colleagues reported in the December 1999 issue of the "American Journal of Clinical Nutrition" that green tea extract containing 90 mg of epigallocatechin and 50 mg of caffeine increased energy expenditure by 80 calories per 24 hours.
Energy Expenditure and Weight Loss
When you burn an extra 80 calories per day, you can expect to lose 1 lb. in 44 days. In other words, you could be 8 lbs. lighter in a year if you add green tea to your daily routine.
Long-term Results of Clinical Trials
The estimate based on Dr. Duloo's short experiment corresponds to findings in clinical trials. Dr. Olivia Phung, a systematic analyst at the University of Connecticut, recently evaluated existing clinical trials that investigated the effect of green tea on body weight. As reported in the December 2010 issue of the "American Journal of Clinical Nutrition, researchers focused on 15 randomized clinical trials. Participants in each trial were randomly assigned to the group that received green tea or to a group that received control pills or drinks. In these 15 trials, 1,243 participants were involved. The studies lasted between eight to 24 weeks. Participants were diverse and included both genders, people of different ages, as well as both lean and overweight individuals. Daily doses of epigallocatechin varied from 576 to 714 mg. When all data were combined, the results indicated that green tea causes weight loss of 3 lbs. per 12 weeks.
- "Journal of the American College of Nutrition"; Beneficial Effects of Green Tea --- A Review; C. Cabrera et al.; April 2006
- "Drug Safety"; Safety of Green Tea Extracts : A Systematic Review by the US Pharmacopeia; DN Sarma et al.; June 2008
- Department of Healthy and Human Services: A Healthier You
- "American Journal of Clinical Nutrition"; Efficacy of a Green Tea Extract Rich in Catechin Polyphenols and Caffeine in Increasing 24-h Energy Expenditure and Fat Oxidation in Humans; AG Duloo et al.; December 1999
- "American Journal of Clinical Nutrition"; Effect of Green Tea Catechins With or Without Caffeine on Anthropometric Measures: A Systematic Review and Meta-Analysis; OJ Phung et al.; Janurary 2010