Green tea is a staple drink in many cultures throughout the world. Green tea is said to have originated from China, but it has become an integral part of the culture in many Eastern countries and is consumed in other countries throughout the world. You have likely had a cup of green tea without even realizing that it has some potential health benefits for your body.
While green tea has been shown to have a variety of great effects for things like tension and joint pain in this article we’ll be focusing on the effects green tea specifically has on fat.
General Effects of Green Tea on Fat
There have been a number of studies looking at the improved metrics for body fat percentage in populations that drink green tea for some time now. Experimental studies that isolate different populations have shown significant results for certain Asian groups and caucasian peoples for the reduction in weight.
Other people groups have yet to be tested in an experimental setting, but the mechanisms behind the weight change are likely the same, so results are likely to follow suit.
In observational studies, researchers have also found that middle-aged women who drink coffee and green tea are less likely to be overweight, have a high body fat percentage, and have larger amounts of plaque build-up. While these studies are only correlational and likely have a strong behavioral confounding variable these findings are still quite interesting.
Green tea has a number of great components that contribute to its health-enhancing powers, but the main two categories are catechins and flavonoids.
Catechins are an important part of green tea’s fat-burning effects. One study looked at the body fat percentage of various men through a 12 weeks period. During this time a control group and an experimental group were both given green tea to drink every day, but the experimental group’s green tea had 690 mg of catechins, while the control group only had 22 mg of catechins.
At the end of the experiment, the researchers found a significant difference in body fat between the two groups. Those that had the catechins had less fat.
One other metric that this study measured is malondialdehyde (MDA). MDA is a highly reactive compound in the body, and it is used most often as a biological identifier of oxidative stress. In those that had the catechins, there was significantly less MDA, oxidative stress, than there was for those who did not have the catechins. This concept of oxidative stress is important, and we'll be coming back to it. But first, let’s discuss the other important factor of green tea - flavonoids.
Flavonoids are 15 carbon, three-ring chemical structures found in various foods. Some foods that have been shown to be the best flavonoid sources include:
- Red wine
- Green Tea
- Cruciferous vegetables
Flavonoids are special because they are polyphenolic compounds, meaning that they have multiple phenol groups. Phenols are the most common chemical structure that is used in the process of reducing oxidative stress. A process catechins are also involved in reducing.
Oxidative stress is naturally occurring in your body due to processes like digestion and metabolism that provide your body with energy and nutrients. During the breakdown of these nutrients into energy or otherwise usable forms, certain molecules lose electrons or their electrons move to lower energy states. In these lower energy states, these compounds are called free radicals, and they are unstable and potentially dangerous to the body.
They react undescrimiantantly with many different molecules and cause damage to integral parts of the cell like the DNA. When a cell faces too much oxidative stress, then it undergoes a process called apoptosis which destroys the cells before it can reproduce and pass along the damaged genes.
Preventing oxidative stress from occurring in the first place is a natural way to defend against this biological damage. While oxidative stress does occur due to metabolism, there are other mechanisms that can ramp up oxidative stress in the body as well: physical stress and emotional stress.
Not working out can have negative health outcomes by not encouraging proper muscle and bone development. Resisting your emotions can only make them last longer and become much greater when they resurface. Oxidative stress is a normal part of life, but keeping it in check can be beneficial.
Phenols naturally combat free radicals by reducing them back to a more stable form, and polyphenols like flavonoids are even stronger.
Mechanisms Fat and Stress
Oxidative stress is not the end all be all of fat-burning since processes that both increase oxidative stress can have varying effects on body fat accumulation. Mental health issues have been shown to increase fat accumulation while working out has been shown to decrease the body fat percentage.
However, there have been studies done that solely look at the relationship between oxidative stress and body fat percentage that have concluded the mechanism for filling white adipose tissue (storage fat tissue, like most abdominal fat) is driven in part by oxidative stress.
During oxidative stress, oxidation products tend not to be removed in an oxidized state which stalls energy production in order to keep equilibrium. When the mitochondria cannot use the energy molecule they get stored, leading to the accumulation of fat.
Green tea has two important components: catechins and flavonoids. Both of these classes of compounds have an important role to play in reducing oxidative stress in your body. Having oxidative stress comes from many natural sources and is a good marker for how hard your body is working, but undue stress can be an indicator and driver of fat accumulation in the body. Oxidative products push the equilibrium of your energy production to the left, meaning that your body will not be able to make as much energy.
This can make you feel fatigued and more stressed. But also, the body still needs to do something with the nutrients it did not turn into energy, so they go to storage. Fat accumulation ensues. The antioxidant effects of green tea can mitigate this process and the evidence suggests a better body fat percentage in the future for those who drink green tea regularly.
Daily Coffee and Green Tea Consumption Is Inversely Associated with Body Mass Index, Body Fat Percentage, and Cardio-Ankle Vascular Index in Middle-Aged Japanese Women: A Cross-Sectional Study | Nutrients
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This article has been reviewed by members of our Scientific Advisory Board.
Dr. Jay Cowin, Nutrition Expert
Founder of Functional U, a Nutrition, Performance & Optimal Health practice.