Green tea is the healthiest beverage on the planet.
It is loaded with antioxidants and various substances that are beneficial for health.
Many studies have shown that green tea can increase fat burning and help you lose weight.
Let me explain how that works...
Green tea is more than just hot, flavored water.
The bioactive substances in the tea leaves dissolve in the water and make it into the final drink.
When you drink a cup of quality tea, you're actually getting a large amount of beneficial substances with potent biological effects ().
Caffeine is a well known stimulant that has been shown to aid fat burning and improve exercise performance in numerous studies (, ).
But where green tea really shines is in its massive range of antioxidants... being loaded with potent antioxidants called ().
The most important of these is EGCG (Epigallocatechin gallate), a substance that can boost metabolism.
Keep in mind that these benefits can be derived both from drinking green tea as a beverage, as well as taking green tea extract as a supplement. Most of the studies used extracts.
Bottom Line: Green tea contains bioactive substances like caffeine and EGCG, whichcan have powerful effects on metabolism.
In order to burn fat, it must first be broken down in the fat cell and moved into the bloodstream.
The active compounds in green tea can aid in this process by boosting the effects of some fat burning hormones.
The main antioxidant in tea, EGCG, can help inhibit an enzyme that breaks down the hormone norepinephrine ().
When this enzyme is inhibited, the amount of norepinephrine increases ().
This hormone is used by the nervous system as a signal to the fat cells, telling them to break down fat. Therefore, more norepinephrine leads to a stronger signal being sent to the fat cell and more fat gets broken down.
Caffeine and EGCG (both found naturally in green tea) may actually have a synergistic effect, because caffeine enhances another step in the same pathway ().
The end result is that the fat cell breaks down more fat, which is released into the bloodstream and becomes available for use as energy by cells that need it, like muscle cells.
Bottom Line: The substances in green tea increase levels of hormones that tell fat cells to break down fat. This releases fat into the bloodstream and makes it available as energy.
If you look at the label of almost every commercial weight loss and fat burning supplement, chances are that you will find some kind of tea there as an ingredient.This is because green tea has been repeatedly shown to increase the burning of fat, especially during exercise.
In one study, men who took green tea extract and exercised burned 17% more fat than men who didn't get the supplement. This study suggests that green tea can boost the fat burning effects of exercise ().
Another study that went on for 8 weeks showed that green tea increased fat burning, both during exercise and during rest ().
There are several studies that agree with this. Green tea selectively boosts the burning of fat, which may lead to reduced body fat in the long term (, ).
Bottom Line: A number of studies show that green tea extract can boost the burning of fat. The effect is even stronger when exercising.
The human body is constantly burning calories.
Even when sleeping or sitting down, our cells are performing billions of functions that require energy.
Several studies suggest that green tea can make us burn more calories, even at rest.
In most studies, this amounts to about a 3-4% increase, although some studies show an increase as high as 8% (, , ).
For a person who burns 2000 calories per day, 3-4% amounts to an additional 60-80 calories per day, similar to what you might expect with a high protein diet.
Although most of the studies were very short in duration (1-3 days), there is also some evidence that the metabolism boosting effect persists in the long term (, ).
In one study of 60 obese individuals, the group taking green tea extract lost 7.3 lbs (3.3 kg) and burned 183 more calories per day after 3 months ().
However, keep in mind that not all studies show that green tea boosts metabolism. The effect may depend on the individual ().
Bottom Line: Several studies show that green tea can boost metabolism and help people burn about 3-4% more calories each day.
One way that green tea could help with weight loss, is by reducing appetite.
This would make us take in fewer calories, automatically, without any effort.
Several studies have looked at the effects of green tea on appetite, but most showed conflicting results ().
There are also animal studies suggesting that green tea can reduce the amount of fat we absorb from foods, but this has not been confirmed in humans (, , ).
Overall, it seems that green tea exerts its effects primarily by increasing "calories out"... it makes us burn more fat, but it doesn't appear to have any noticeable effect on how much food we end up eating throughout the day.
Bottom Line: There is currently no evidence that green tea makes people eat fewer calories. Some studies in animals suggest that it may reduce the absorption of fat from the diet, but this has not been confirmed in humans.
When it comes to actual pounds losts, the effects of green tea are relatively modest.
Although there are numerous studies showing that people do in fact lose weight, there are also some studies showing no effect.
Two review studies that looked at many controlled trials found that people lost about 3 pounds (1.3-1.4 kg) on average (, ).
However... it's important to keep in mind that not all fat is the same.
We have subcutaneous fat that lodges under the skin, but then we also have visceral fat, which is the belly fat that builds up around the organs.
It is this deep visceral fat that is harmful. It causes and insulin resistance, both of which are strongly linked to all sorts of serious diseases, including type 2 diabetes and heart disease.
Several studies on green tea show that although the weight loss effects are modest, a significant percentage of the fat lost is the harmful visceral fat (, , ).
This should translate to a reduced risk of many killer diseases down the line... which may lead to a longer and healthier life.
Even though green tea can mildly increase metabolism and fat burning, the effects are modest when it comes to actual pounds lost.
Of course... let's not forget that green tea goes way beyond just body weight. It is also extremely healthy for various other reasons.
If you want to read more about the many impressive health benefits of green tea, then check out this article: Top 10 Evidence-Based Health Benefits of Green Tea.