By Nicole Martinez
Clinical Nutritionist Educator
Tea is among the most popular beverages in the world. It is second only to water in terms of how much it is consumed worldwide. Green tea, specifically, has been enjoyed for centuries for its flavor and health benefits. Recently, there has been growing interest in green tea as a weight-loss aid.
What makes green tea green?
True tea comes from the Camellia sinensis plant, and comes in many different varieties. Green tea differs from the more popular black tea in that the harvested leaves are not exposed to air, and therefore not oxidized. Green tea originated in China, but is now produced in Japan and India as well. After harvesting, the leaves may be steamed, producing a bright green tea or roasted in a wok, which creates a pale green-colored tea.
Green tea’s health benefits stem from its high antioxidant content. Antioxidants are chemical compounds that can protect our cells from damage and may help protect us against cancer and heart disease. Green tea contains a variety of antioxidants including catechins, theaflavins and the flavanol quercitin. Green tea also contains caffeine, about 25 mg per 8 oz. cup, which is about one-third the caffeine in an 8 oz. cup of coffee.
Can green tea help you lose weight?
According to current research, the antioxidants and caffeine present in green tea seem to cause an increase in metabolic rate. In theory, increasing metabolic rate would cause more calories to be burned, which could lead to weight loss. This effect, however, is minimal and most likely will not show up on the scale.
A 2009 meta-analysis of 11 studies did show a positive effect between catechins and weight loss, but since most studies isolate these compounds it is difficult to pass these results on to brewed green tea.
Supplements vs. the real thing
There are many green tea supplements available that claim to boost metabolism and burn fat, but most experts, including the American College of Gastroenterology, recommend avoiding these supplements due to reports of liver damage.
If you are interested in adding green tea to your diet, avoid supplements and instead enjoy a brewed cup. According to the Institutes of Medicine, it is just as hydrating as water, and up to 9 cups per day is considered safe.
General health benefits
As for the health benefits of green tea, research does show that it may help protect against cardiovascular disease by preventing the oxidation of LDL cholesterol and reducing blood clotting. A meta-analysis of 13 randomized controlled trials, showed that it significantly lowered blood pressure, as well as LDL cholesterol and total cholesterol. So, adding a few cups of unsweetened green tea each day may be beneficial for heart health.
When it comes to weight loss, there is no substitute for healthy eating, reduced calories and increased exercise. Replace sugary beverages with unsweetened green tea to reduce calories, and enjoy drinking it for its possible cardiovascular benefits, but avoid costly and possibly dangerous supplements. Green tea can be enjoyed hot or iced and can be brewed with herbal or fruit teas for interesting alternatives to plain water and healthy alternatives to sugary beverages.
Nicole Martinez, MHS, RD, LDN, is a Clinical Nutritionist Educator with Mission Weight Management.
- http://www.todaysdietitian.com/newarchives/0716p28.shtml 
- https://www.consumerreports.org/dieting-weight-loss/truth-about-green-tea-for-weight-loss/ 
- https://gi.org/media/current-press-releases-and-media-statements/dili-guidelines/