Green tea and its extracts have gained immense popularity as beverages and supplements, often hailed for their potential health benefits, including weight loss. But does green tea truly live up to the hype? This article delves into the science behind green tea, examining its potential role in weight loss, its other health benefits, and optimal ways to incorporate it into your diet.
What is Green Tea?
Green tea, also known as "unoxidized tea," originates from the Camellia Sinensis plant, the same source as black tea. Initially used for medicinal purposes, green tea gained popularity among the wealthy during the Tang Dynasty (600-900 AD) as a beverage enjoyed for its flavor. While it eventually reached Europe and the Americas, its health benefits and unique flavor have only recently been widely recognized.
Green tea is traditionally harvested by hand, with the leaves immediately cooked to preserve their green color and prevent oxidation. This contrasts with black tea production, where leaves are harvested, rolled, and allowed to oxidize, resulting in their characteristic black color. Green tea boasts a higher concentration of chlorophyll, polyphenols, and antioxidants compared to black and oolong teas. It is particularly rich in the antioxidant catechin, specifically epigallocatechin gallate (EGCG).
Numerous varieties of green tea exist, primarily originating from China and Japan. Popular examples include the Chinese Longjing and gunpowder teas, as well as the Japanese sencha and tencha teas. Matcha green tea is a powdered form of tencha tea leaves and is the primary tea used in traditional Japanese tea ceremonies.
Can Green Tea Aid Weight Loss?
Green tea's popularity has surged in recent years, largely due to its perceived wellness benefits, including weight loss. Caffeine and EGCG, two key components of green tea, are believed to contribute to fat burning and weight loss, although the extent of their impact remains under investigation.
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Animal studies have shown promising results with green tea extracts, demonstrating significant weight loss alongside reductions in blood glucose, insulin resistance, visceral fat accumulation, and plasma cholesterol levels. However, human studies have yielded variable results, with only limited and mild weight loss benefits observed.
Some studies suggest that a short-term combination of caffeine and catechin EGCG may slightly boost metabolism, increasing energy expenditure and fat oxidation. A meta-analysis revealed that both catechin and caffeine in tea boosted energy expenditure for over 24 hours, and their combination increased fat oxidation rates. However, longer-term studies have been less conclusive, with a systematic review finding a very small (and not statistically significant) effect on weight loss from drinking green tea over 12 weeks. While the effects of green tea on weight loss are conflicting, its potential to oxidize fat, especially visceral fat, is promising. Reducing visceral fat may lower the risk of chronic diseases like metabolic syndrome, insulin resistance, diabetes, and heart disease.
Hot vs. Cold Green Tea
The temperature of the beverage has little to no effect on your ability to burn extra calories. Hot or cold, the temperature of the beverage you choose has little to no effect on your ability to burn extra calories. The bigger question is if one type of tea brewing method produces and preserves more health-promoting antioxidants than others, which may affect how much weight you can lose. Both hot and cold brew teas release similar amounts of catechins and have similar antioxidant capacity. Cold-brewing tea takes longer to reach the same level but may have a milder flavor. One study found that the phenol and caffeine content is better preserved by adding ice to hot tea than in hot or cold brewed tea alone. Hot water allows for the greatest extraction of phenols and caffeine while chilling it quickly diminishes oxidation. If you find the flavor of hot-brewed teas too intense, give cold brewing a try. Add tea leaves or tea bags to cold water and let them infuse overnight. Your mild-flavored tea will be ready for you first thing in the morning!
Matcha Green Tea
Matcha green tea, a powdered form of the Japanese tencha variety, stands out as a high-quality green tea. Shade-grown to enhance its amino acid and antioxidant content, matcha boasts a vibrant green color and a smooth, savory flavor. Containing higher levels of EGCG compared to other green teas, matcha also offers a slightly higher caffeine content.
Matcha also contains quercetin, an antioxidant that may reduce oxidative stress and inflammation, support cognitive function, and improve insulin sensitivity. Combined with EGCG, quercetin may exhibit enhanced anticarcinogenic effects. Like other green teas, matcha's EGCG content may inhibit fat and glucose absorption in the GI tract and improve insulin sensitivity.
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The impact of matcha on weight loss is variable. A small study found that women who drank matcha green tea while engaging in brisk walking experienced increased fat oxidation. While promising, more research is needed to confirm these findings. If the flavor of matcha is a bit too bitter for you, try adding a teaspoon of matcha powder to your morning green smoothie or make a matcha latte with hot milk (or a dairy-free milk alternative).
Decaffeinated Green Tea
Given that caffeine is believed to contribute to green tea's weight loss effects, decaffeinated green tea might seem less effective. However, some research suggests otherwise. A recent study with overweight girls found that consuming decaffeinated green tea polyphenols resulted in decreased percent body fat over 12 weeks. A typical cup of regular green tea contains significantly less caffeine than a cup of coffee. If you are caffeine-sensitive, stick with decaffeinated coffee and enjoy its flavor and other health benefits.
Bottled Green Tea
Bottled green teas can offer a consistent composition of catechins and other bioactive compounds due to their manufacturing under controlled conditions. However, it's crucial to be mindful of added sugar and sweeteners, such as high-fructose corn syrup, sugar, or artificial sweeteners, in many brands. Read the nutrition label and ingredient list carefully on bottled teas. Look for an unsweetened version or find a version that has no more than 5 grams of added sugar and uses a natural sweetener like monk fruit.
Other Health Benefits of Green Tea
While green tea's impact on weight loss may be modest, it offers numerous other potential health benefits, including:
- Reduced inflammation: Green tea's antioxidants, especially EGCG and quercetin, can help protect against free radical damage and reduce inflammation.
- Reduced risk of cancer: EGCG's potential to reduce inflammation and protect cells against oxidation has long been linked to a reduced risk of some cancers. However, more research is needed to confirm these effects.
- Reduced risk of metabolic syndrome: Green tea may help decrease visceral "belly" fat, a key factor in metabolic syndrome.
- Reduced risk of type 2 diabetes: Green tea may improve insulin sensitivity and help regulate blood sugar levels.
- Reduced risk of cardiovascular disease: Green tea's flavonoids may help lower cholesterol levels, open blood vessels, and improve blood flow.
- Improved insulin sensitivity: Green tea may enhance the body's response to insulin, a hormone that regulates blood sugar.
- May help improve mood and memory: Amino acids like L-theanine and catechins like EGCG have brain-protective benefits.
EGCG and caffeine may also decrease inflammation and oxidative damage in the brain and heart and support the immune system. EGCG may inhibit carbohydrate digestion and lipid absorption into fat cells, helping to reduce blood glucose and decrease lipid levels.
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Potential Drawbacks of Green Tea
Despite its benefits, green tea consumption may have potential drawbacks. If you are sensitive to caffeine, opt for a decaffeinated version to avoid caffeine-associated side effects. High amounts of green tea or green tea extract may reduce the blood levels of beta-blockers, a type of blood pressure medication. Check with your doctor or pharmacist if this is a concern. In rare instances, some individuals have experienced liver problems when taking green tea extract. If you have liver disease, consult your doctor before adding green tea to your routine or starting a green tea extract supplement.
Integrating Green Tea for Weight Management and Overall Health
Overall, green tea is a healthful beverage choice for most people. The powerful antioxidant EGCG may have some effect on visceral fat, but donât rely on EGCG alone to meet your weight loss goals. Your best bet is to combine a cup of tea with a healthy diet and exercise to maximize your weight loss efforts.
While the ability of green tea to help with weight loss may still be questionable, consider the additional health benefits you may get from enjoying a cup or two of green tea each day.
Deciding to give green tea a try? Go for it! Just remember that green tea with sweeteners or milk may affect your blood glucose levels. You can monitor your blood sugar response with your CGM and the Signos app to see how adding green tea to your routine affects your blood glucose levels.
Recommendations for a weight loss
- making a specific plan with realistic goals
- exercising regularly
- getting plenty of sleep
- managing stress
- aiming for slow, steady weight losses
- eating a balanced diet with all the necessary nutrients
- keeping a food diary
- seeking support from friends, family, or support groups