I can’t believe I haven’t posted on this topic yet!! I did some research on green tea and its correlation with weight loss a little while ago with one of my dietetics friends, Kristen Heitman (this girl is a gem and a half. A dietetic superstar, if you will) Here is a summary of our findings!
What can green tea do for me?
Green tea has been proven to act against cancer, diabetes, high cholesterol, liver disease, inflammatory bowel disease, and aid in weight loss and weight management.
Why can it do this?
One of the most powerful ingredients found in green tea that contributes to its anti-obesity properties are catechins. Catechins area powerful, natural polyphenol flavanoid antioxidants. Antioxidants protect the body from free radicals, which steal electrons from another healthy cell in the body to begin a chain reaction causing cellular damage. This process has been shown to occur naturally with age. Cellular destruction by free radical degeneration can affect DNA cells, melanin cells, and other healthy cells in the body. Catechins contain properties that work to reduce bacteria, heart disease, cancer, and body weight reduction properties to name a few. Epigallocatechin gallate (EGCg) is the most powerful catechin antioxidant. Green tea contains a much higher amount of EGCG than any other type of tea, which is the cause of its growing popularity.
Is there any evidence?
(sorry if this stuff is a little dense! It is worth it.. I promise!)
In a study based on 11 different research articles a strong correlation was reported. When only adding green tea to ones diet, making no other changes, there is shown to be a significant effect on decrease in body weight and weight
management, with a p-value of <0.001. Although this shows a positive correlation, it does not define the diets, lifestyles, or any other implications of those that were observed to obtain this data. Another study that was performed on diet-induced obese mice. While maintaining a high fat diet, the mice that were taking green tea supplements had decreased levels of plasma triglycerides and liver lipids, as well as a reduction in adipose tissue. While green tea has incredible health benefits, the studies researched lead one to believe that the anti-obesity effects of green tea are most prominent in those who are over-weight and/or consuming a high fat diet. Other moderators can affect anti-obesity effects such as level of activity and various other lifestyle choices.
In addition to powerful antioxidants, green tea also contains caffeine. Caffeine is a stimulant that affects the central nervous system. It stimulates muscle, as well as brain, exercise while also heightening stamina, allowing one to exercise harder and longer. Thermogenic, or fat burning, properties are another affect of the caffeine present in green tea. When combined with exercise, it enhances the metabolization of adipose fat rather than dipping into glycogen sources resulting in a decrease in excess adipose tissue.
Studies have shown that Green Tea can increase the body’s metabolic rate, and therefore, speed up fat oxidation. Caffeine is another stimulant that is known to speed up the body’s metabolic rate, although it is possible for the body to become immune to these changes after a period of normal consumption.
Based on our research, it is recommended to consume 3 cups of caffeinated freshly brewed green tea a day to assist in weight loss and weight management. This approach has been proven to be effective.
Overall, green tea is successful in aiding in weight management in those without major health problems. The mean weight lost in this study was 2.9 pounds (1.31 kg). Note that this is not a replacement for a healthy diet and exercise, but more of something to add on to give you that extra boost.
Drink up, Cheers!
American Cancer society, Green Tea. http://www.cancer.org/Treatment/TreatmentsandSideEffects/ComplementaryandAlternativeMedicine/HerbsVitaminsandMinerals/green-tea (April, 2012)
Camira Bailey, Catechin Weight Loss.
http://www.livestrong.com/article/495436-catechin-weight-loss/ (April, 2012)
Mak-Soon Lee, Chong-Tai Kim, Yangha Kim. Body Weight with Regulation of Multiple Genes Expression in Adipose Tissue of Diet-Induced Obese Mice. Annalysis of Nutrition and Metabolism. 54: 151-157, 2009
Maryland Medical Center, Green Tea. http://www.umm.edu/altmed/articles/green-tea-000255.htm, (April, 2012)
Westerterp-Plantenga. Green tea catechins, caffine and body-weight regulation. Journal of Physology & Behavior. 02(005): 42-46, 2010.
Thavanesan, Navamayooran. The putative effects of green tea on body fat: an evaluation of the evidence and a review of the potential mechanisms. British Journal of Nutrition.: 1-13, 2011