Green Tea For Weight Loss
Green tea is used in weight loss products mainly for its ability to help boost the body’s metabolism. Some use green tea for weight loss religiously, but how effective and safe is it? This article looks at evidence based research on green tea supplements and teas and if they are the answer to your weight loss problems.
Green tea is a new and popular weight loss tool that has many different benefits, one of which is the ability to help eliminate excess weight. While it is true that green tea cannot melt away fat on its own, it can still be very useful in weight loss efforts. By drinking more green tea, you might experience some weight loss from increased water-intake, the control of drinking sweetened beverages by drinking unsweetened ones, and other health benefits outside of weight loss.
What is green tea?
Tea comes in different varieties, but all are derived from the same plant. Green, black, white, and oolong tea are produced from the Camellia sinensis plant.
Green tea is manufactured by steaming the leaves of the Camellia sinensis plant. It does not go through the same fermentation process used to make other types of tea, such as oolong or black tea, so it retains more of the antioxidants and nutrients found in the plant leaves.
How Green Tea Can Help You Lose Weight
- Fat Loss
- How It Works
- Burning Fat
- Calorie Restriction
- Belly Fat
- Bottom Line
Green tea is one of the healthiest beverages on the planet.
It is loaded with antioxidants and various plant compounds that may benefit your health.
Some people even claim that green tea can increase fat burning and help you lose weight.
This article examines the evidence surrounding green tea and weight loss.
Contains Substances That Can Help You Lose Fat
Tea leaves contain many beneficial compounds.
One of green tea’s compounds is caffeine. Although a cup of green tea holds much less caffeine (24–40 mg) than a cup of coffee (100–200 mg), it still contains enough to have a mild effect.
Caffeine is a well-known stimulant that has been found to aid fat burning and improve exercise performance in numerous studies
However, green tea really shines in its antioxidant content. Studies show that drinking a cup of green tea increases the amount of antioxidants in your bloodstream
This healthy beverage is loaded with potent antioxidants called catechins
The most important of these is epigallocatechin gallate (EGCG), a substance that can boost metabolism.
Although one cup of green tea may raise your antioxidant levels, most studies have examined the benefits of green tea extract — which is a concentrated source of catechins.
Green tea contains bioactive substances like caffeine and EGCG, which can have powerful effects on metabolism.
Can Mobilize Fat From Fat Cells
To burn fat, your body must first break it down in the fat cell and move it into your bloodstream.
Animal studies suggest that the active compounds in green tea can aid this process by boosting the effects of some fat-burning hormones, such as norepinephrine (noradrenaline).
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, promoting fat breakdown
In fact, caffeine and EGCG — both of which are found naturally in green tea — may have a synergistic effect
Ultimately, your fat cell breaks down more fat, which is released into your bloodstream for use as energy by cells like muscle cells.
Compounds 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.
Increases Fat Burning, Especially During Exercise
If you look at the label of almost every commercial weight loss and fat-burning supplement, you will likely see green tea listed as an ingredient.
This is because green tea extract has been repeatedly linked to increased fat burning, especially during exercise.
In one study, men who took green tea extract before exercise burned 17% more fat than men who didn’t take the supplement. The study suggests that green tea can boost the fat-burning effects of exercise
An eight-week study determined that tea catechins increased fat burning, both during exercise and rest
Several other studies confirm these findings, indicating that EGCG boosts the burning of fat — which may lead to reduced body fat in the long term
A number of studies show that green tea extract can boost fat burning. The effect is even stronger during exercise.
Boosts Your Metabolic Rate
Your body is constantly burning calories.
Even when you’re sleeping or sitting down, your cells are performing millions of functions that require energy.
Several studies suggest that taking green tea extract or EGCG supplements can make you burn more calories — even at rest.
In most studies, this amounts to about a 3–4% increase, although some show an increase as high as 8%
For a person who burns 2,000 calories per day, 3–4% amounts to an additional 60–80 calories spent per day — similar to what you might expect from a high-protein diet.
Although most of these studies were very short in duration, some evidence suggests that the metabolism-boosting effect persists in the long term
In one study in 60 obese individuals, those taking green tea extract lost 7.3 more pounds (3.3 kg) and burned 183 more calories per day after three months than those not taking the extract
However, not all studies show that green tea extract boosts metabolism. The effect may depend on the individual
Several studies suggest that green tea can boost metabolism and help people burn 3–4% more calories each day.
Can It Automatically Make You Consume Fewer Calories?
One way that green tea could aid weight loss is by reducing appetite.
This would theoretically make you consume fewer calories automatically — and without any effort.
However, studies produced conflicting results on the effects of green tea on appetite
Some animal studies suggest that green tea extracts or EGCG supplements can reduce the amount of fat you absorb from foods, but this has not been confirmed in humans
Overall, green tea’s primary effect is to increase calorie expenditure, making you burn more fat — but it doesn’t appear to have any noticeable effect on how much food you end up eating throughout the day.
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 human studies have not confirmed this.
Green Tea Can Help You Lose Fat, Especially Harmful Abdominal Fat
When it comes to actual pounds lost, the effects of green tea are relatively modest.
Although many studies show that people do in fact lose weight, there are also some studies showing no effect.
Two reviews of many controlled trials on green tea supplements found that people lost about 3 pounds (1.3 kg) on average
Keep in mind that not all fat is the same.
Subcutaneous fat lodges under your skin, but you may also have significant amounts of visceral fat, also called belly fat.
High amounts of visceral fat are associated with inflammation and insulin resistance, both of which are strongly linked to several serious diseases, including type 2 diabetes and heart disease.
Several studies on green tea catechins show that although the weight loss effects are modest, a significant percentage of fat lost is harmful visceral fat (25Trusted Source, 26, 27Trusted Source).
Therefore, green tea should reduce your risk of many major diseases down the line, which may lead to a longer and healthier life.
Green tea extract or catechin supplements may help you lose visceral fat — a fat that is particularly harmful to your health.
Robust Research on Tea and Weight Loss Is Lacking
That said, many studies look at the effects of tea in capsule or tablet form, which may provide study participants with a more concentrated dose of plant compounds like EGCG than a typical bag of tea would. Other studies don’t use humans, and if they do, the population sizes are on the smaller side. These are major limitations, so more large studies in humans using brewed tea are needed before scientists understand and can better determine any potential weight loss benefits for people.
Regardless, health experts agree that plain, unsweetened brewed tea is generally healthy. Go ahead and prepare that cup — and as you sip, check out this list of the top teas for weight loss, in order from strongest evidence to weakest.
Most conversations about tea and weight loss tend to start with green tea — and for good reason. Of all the teas, this mild, bittersweet variety has the most research to back up its potential weight loss benefits.
For example, a previous study of about 1,200 Taiwanese men and women found that those who drank two cups of green tea per day for more than 10 years had a lower percentage of body fat and a smaller waist than non-regular green tea drinkers. The researchers simply observed an association between drinking green tea and having a smaller waist, not a cause-and-effect relationship. Also, the researchers relied on survey data, which may have left room for error.
Other studies have suggested a more direct link between green tea and weight loss, though this research also has limitations, including study size and length, as well as a lack of using brewed tea. In a very small past laboratory study, 10 healthy men burned an extra 63.5 to 200 calories in 24 hours after taking two green tea extract supplements three times in one day, compared with a day when they took a placebo. These small increases may help people lose weight over time, but long-term health risks versus benefits would need to be explored in a larger study.
The calorie-burning effects of green tea may stem from the combined effects of EGCG and caffeine, which appear to work synergistically: “Studies have reported that caffeine must be present with EGCG to aid in weight loss, because a stimulated nervous system is needed for optimal results,” Koszyk says. According to a review of 15 clinical trials published in June 2017 in Nutrición Hospitalaria, green tea was only effective for weight loss when it was combined with 80 to 300 milligrams (mg) of caffeine per day.
Moreover, the EGCG and caffeine in green tea may target fat cells in particular. Another small study involving 10 men who were obese or overweight found that taking 300 mg of EGCG in supplement form for three days helped increase fat oxidation (the process of breaking down fatty acids). Per past research, 300 mg of EGCG is about what you’d find in three cups of brewed green tea.
“In addition, EGCG can inhibit fat cell development, so the body doesn’t form new fat cells,” Koszyk says. Research in animals suggests that the catechins in green tea interfere with the process of fat absorption and metabolism, according to a past article.
However, newer research is needed to determine the actual effects of green tea on weight loss, due to the aforementioned limitations to previous studies.
After they’re harvested, black tea leaves are allowed to oxidize — that is, soak up the surrounding air — longer than other teas, according to a past review. This intensifies the flavor, making black tea one of the boldest varieties on the market.
Prolonged oxidation, which is commonly referred to as “fermentation,” also changes the makeup of polyphenols, or plant compounds, in black tea. While it does contain EGCG like less-processed tea varieties, it’s a better source of theaflavins. These polyphenols form when black tea leaves are oxidized, and they may offer weight loss benefits, according to a review published in April 2018 in Molecules.
For example, a past study found that men and women who drank three cups of powdered black tea per day gained less weight and slimmed their waistlines after three months, compared with those who didn’t drink black tea. But these changes had not continued at a six-month follow-up point, so these effects of black tea appear to be limited.
Retelny says that the polyphenols in black tea may work by lowering calorie intake and decreasing the absorption of fats and carbs.
The polyphenols may also alter gut bacteria in a way that combats obesity. In a study published in September 2017 in the European Journal of Nutrition, researchers fed a group of obese mice a high-fat, high-sugar diet and supplemented it with black tea extract. After four weeks, these animals dropped to the same weight as a group of obese mice that were fed a low-fat diet. When researchers took samples from the animals’ intestines, they found that the black tea group had fewer gut bacteria associated with obesity and more bacteria related to lean tissue. The results are far from conclusive though. More research is needed to see if these effects hold true for humans.
This partially oxidized tea is a popular pick with a bolder flavor than green tea, yet one that is milder than black.
Oolong contains a mixture of polyphenols that give green and black tea their claim to fame: catechins (green tea) and theaflavins (black tea), according to a past review. Like these other tea varieties, oolong also provides caffeine and may promote weight loss.
For example, a study published in February 2018 in Nutrients found that oolong tea extract helped increase fat burning in mice.
Other research suggests these benefits may be true in humans, too, though larger studies are still needed. A small study involving 12 participants that was published in December 2020 in Nutrients found that men without obesity who drank oolong tea at breakfast and lunch saw a 20 percent boost in post-meal fat burn after 14 days. Men who drank an experimental caffeine beverage saw similar results. Still, they didn’t burn as much fat during sleep as the oolong group, suggesting that the tea’s caffeine content isn’t solely responsible for its effects.
The fat-burning effects of oolong tea may lead directly to weight loss by aiding lipid metabolism, some researchers theorize. For example, a past study found that drinking four cups of oolong tea per day helped adults who were overweight or obese lose weight. In fact, roughly 70 percent of the subjects with severe obesity (those with a body mass index higher than 35) lost more than 2.2 pounds by the end of six weeks, and 22 percent lost more than 6 pounds.
But while some studies show promise, more research is needed to determine if and how oolong tea helps with weight loss, Koszyk notes.
According to a past review, white tea is the least processed of all the teas, which accounts for its light, delicate flavor. The minimal processing also means white tea holds onto a high amount of anti-inflammatory antioxidants and fat-burning EGCG, making it another potentially beneficial brew for trimming weight.
“White tea has been suggested to help speed up the breakdown of fat cells and block the formation of new ones, so it can potentially offer weight loss benefits,” Koszyk says.
For example, a past test-tube study found that white tea extract did precisely that: stimulate the breakdown of human fats and prevent new fat cells from forming. According to researchers, these effects were in large part thanks to EGCG.
Test-tube studies can help direct future research. “In-vitro studies allow us to test hypotheses in a controlled environment using specific cells without distractions or complications that other variables bring when using human subjects,” Koszyk says. However, the results don’t necessarily translate to actual human beings, she adds. Those human studies are still needed.
This tart, tangy tea — harvested from hibiscus leaves — offers catechins like EGCG and has been shown to help lower blood pressure and cholesterol, Retelny says. One past review of animal and human studies, for instance, suggests that hibiscus extract shows promise in the treatment of high blood pressure and high cholesterol, though the authors say we need more research before recommendations can be made.
It may also help you keep your weight at a healthier level. In a past study, adults who were overweight or obese who took a hibiscus extract for 12 weeks had reduced body weight, body mass index, body fat, and hip-to-waist ratio, compared with a control group. The researchers attributed those perks to the plant compounds in the hibiscus extract.
Another study reported similar results from feeding obese mice hibiscus extract for 60 days, though studies of similar duration haven’t been conducted in humans.
Unfortunately, current research is limited to hibiscus extract. More research with liquid tea is needed before scientists can make any conclusions about its effectiveness for weight loss.
“There is no magic elixir for weight loss,” Koszyk says. “Drinking tea can help improve hydration and increase metabolism, but for sustainable weight management, you need to make dietary and lifestyle changes.”