Green tea offers numerous health benefits. It has been used in Chinese medicine to treat many illnesses for hundreds of years. In recent years, green tea has also been linked to weight loss. The catechins in green tea help to elevate the metabolic rate and increase fat oxidation. In this article, we will look at the research that links green tea to weight loss.
What is green tea?
Green tea comes from the leaves of the Camellia sinensis plant. It is grown in the mountainous regions of East Asia. Unlike black tea, which undergoes fermentation that transforms its flavor and color, green tea remains unprocessed and retains its color. Some green tea is still picked up by hand, as it is believed that hand-picked green tea is less bitter and has a more robust taste.
According to some historians, the origins of green tea date back to 3000 years ago when people who grew tea ate fresh tea leaves for recreation. It was much later that they started plucking tea leaves to process them and steep them in hot water.
- Also read: Periodontal Health Benefits of Green Tea
The caffeine content in green tea
Green tea has lower caffeine content than black tea and coffee. Life all drinks cultivated from caffeinated plants; it is difficult to determine the specific levels of caffeine per cup. The amount of caffeine depends on how the tea is processed and prepared.
|Beverage (8oz.)||Average caffeine content|
|Green Tea||30 to 50 mg|
|Black tea||25 to 110 mg|
|Instant coffee||27 to 173 mg|
|Brewed coffee||102 to 200 mg|
|Espresso||240 to 720 mg|
|Yerba mate||65 to 130 mg|
|Soft drinks||23 to 37 mg|
|Energy drinks||72 to 80 mg|
How does green tea help in weight loss?
1. Contains bioactive compounds
Green tea has several essential compounds that help in weight loss. It contains 30 % polyphenols, including large amounts of a catechin called EGCG (1). Catechins are antioxidants that prevent cell damage and are also known to boost metabolism. Green tea also contains caffeine. Several studies have shown that caffeine can aid fat burning and improve exercise performance (2, 3).
2. Promotes fat breakdown
Our body must break down the fat in the fat cells and move it to the bloodstream, to burn fat. Green tea boosts the effect of some fat-burning hormones like norepinephrine. EGCG in green tea helps to inhibit the hormone the breaks down norepinephrine. This process helps to increase the amount of norepinephrine, and this further leads to fat breakdown (4). According to the University of Fribourg, Switzerland, synergistic interaction between catechin-polyphenols and caffeine can augment and prolong sympathetic stimulation of thermogenesis and can help manage obesity (5).
3. Boosts fat burning during a workout
Green tea is a part of many popular workout supplements on the market. It is used widely by people like bodybuilders and runners who want to increase the fat-burning effect of exercise. Epigallocatechin gallate (EGCG), a potent antioxidant, is responsible for the enhanced fat-burning properties of green tea. According to research from the University of Birmingham, when healthy young men took green tea extracts before exercise, they burned 17% more fat than the men who took the placebo (6).
Another study showed that fat burning was significantly increased by the combination of tea catechins and regular exercise as compared to exercise alone (7). Green tea also includes caffeine, which improves endurance, strength, and speed, which further helps burn more calories and fat.
4. Reduces appetite
Green tea contains caffeine, which is a well-known stimulant that reduces appetite and helps in weight loss. EGCG, one of the most active compounds in green tea, inhibits the breakdown of the enzyme that would typically breakdown catecholamines. Catecholamines activate the sympathetic nervous system and reduce the desire for food. According to a study from the University of Washington, beverages like green tea that contain caffeine and catechins suppress hunger and lead to less energy consumption at the next meal (8)
Research shows that individuals who drink green tea can boost up to 100 extra calories per day due to catechins. This calorie expenditure is similar to what you may expect with a high-protein diet. The caffeine and EGCG content of green tea can increase energy expenditure by 4% to 8% percent according to different studies (9, 10). Though most of these studies suggest short-term improvements in metabolism, some studies also show that green tea can stimulate thermogenesis over a long period, and can affect body mass (11).
Losing fat in the abdominal area can be a challenging process. This fat is linked to inflammation and insulin resistance. During a study by Provident Clinical Research, Bloomington, 132 participants drank green tea or a control beverage for 12 weeks. They also walked at least 180 minutes per week. At the end of the 12 weeks, though there was not much difference in the total fat loss, the green tea group saw more significant changes in the abdominal fat area, subcutaneous abdominal fat area, and fasting total serum triglycerides (12). Losing abdominal fat also reduces the risk of major illnesses later in life.
Other health benefits
- Helps regulate glucose levels and prevent insulin spikes
- Improves various aspects of brain function like mood, memory, reaction time and vigilance
- Lowers the risk of some cancers like breast cancer, prostate cancer, and colorectal cancer
- Lower the risk of Alzheimer’s and Parkinson’s disease
- Improves dental health and reduces infection risk
- Reduces cholesterol levels which help lower the risk of cardiovascular disease
- Helps to reduce the appearance of wrinkles and other signs of aging
Different varieties of green tea
Sencha is one of the most popular varieties of Japanese green tea. The leaves of this tea are first steamed and then shaped. This tea has a bright yellowish-green color and has a sweet, grassy, and slightly astringent flavor.
This tea is made from the tea leaves that are grown in the shade. These leaves have a higher chlorophyll content, which makes them more vibrant. These leaves are ground into a powder. This powder is mixed with boiling water and whisked before being served. Matcha tea is light and sweet, which makes it a popular addition for deserts.
How to buy and store green tea?
Green tea is available as fresh leaves in tea bags and is also blended with other flavors like lemon. Whenever you buy tea leaves, avoid older leaves. Green tea does not stay fresh for very long. It has a shelf life of only six months. Once you have purchased and opened the tea, keep leaves in an air-tight container and store in a cool place to slow down the reactions that reduce the phytonutrient content and impact on flavor.
What is the right way to brew green tea?
Boiling water will destroy the catechins in green tea, so you must take extra care. Bring the water to a boil and then let it rest for ten minutes. Pour this water over the tea and let it brew for one minute before serving. You can make the brew time longer or shorter, depending on your taste.
How much green tea should you drink in a day?
Drinking as little as one cup of green tea per day can also show some improvements in your health. However, three to five cups of green tea are considered ideal for gaining all the benefits of green tea. Consuming too much can lead to some side effects.
Side effects of green tea
Green tea is safe for most adults when taken as a drink in moderate amounts. However, it can lead to some side effects due to its active compounds. These include –
- People with caffeine sensitivities may experience an upset stomach, nausea, irritability, anxiety, and insomnia.
- People who take blood thinners should avoid green tea.
- If you are taking stimulant drugs, green tea can increase your blood pressure.
- Green tea can reduce iron absorption from food.
- Green tea supplements are unregulated by the FDA and may also contain other harmful substances.
- Pregnant and breastfeeding women, people with heart problems, and high blood pressure, kidney and liver issues, stomach ulcers, or anxiety disorders should not use green tea supplements.
Green tea is a popular drink that is consumed worldwide. It is known for its high antioxidant content and numerous health benefits. Green tea has several essential compounds that help in weight loss. Catechin called EGCG helps breakdown fat in fat cells. Green tea also helps increase fat burning during a workout. It helps lose belly fat. It reduces appetite and boosts metabolism.
Always buy fresh green tea and store it in an air-tight container. Do not have more than three to five cups of green tea in a day. The side effects of green tea include insomnia, anxiety, upset stomach, and nausea. Pregnant and breastfeeding women, people with heart problems, and high blood pressure, kidney and liver issues, stomach ulcers, or anxiety disorders should not use green tea supplements.