Green tea and weight loss
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Green Tea and Weight Loss: Evidence from Clinical Trials and Reviews
Green Tea Extracts, Catechins, and Weight Loss in Adults
Multiple studies have examined the effects of green tea and its main active components, such as catechins and epigallocatechin gallate (EGCG), on weight loss. Meta-analyses and systematic reviews show that green tea preparations can lead to small reductions in body weight, body mass index (BMI), and waist circumference in overweight or obese adults, but the effects are generally modest and may not be clinically significant for most people 1479. For example, one large review found that green tea led to a mean weight loss of about 1–2 kg compared to placebo, but the certainty of this evidence is low and the results are not always consistent across different populations 1479.
High-Dose Green Tea Extract and Central Obesity
A clinical trial using high-dose green tea extract (EGCG) in women with central obesity found significant reductions in body weight, BMI, and waist circumference after 12 weeks of supplementation. The study also reported improvements in cholesterol levels and beneficial changes in hormones related to appetite and fat metabolism, with no significant side effects . This suggests that higher doses of green tea extract may have a more noticeable effect, especially in specific groups such as women with central obesity .
Mechanisms of Action: Fat Oxidation, Hormones, and Metabolism
Green tea’s weight loss effects are thought to be due to increased fat oxidation, inhibition of fat absorption, and changes in hormones that regulate appetite and fat storage. EGCG and other catechins may activate enzymes that help break down fat and reduce the formation of new fat cells 36810. Some studies also suggest that green tea can lower levels of the hunger hormone ghrelin and increase adiponectin, a hormone that helps regulate glucose and fat metabolism 2610.
Factors Influencing Effectiveness: Ethnicity, Caffeine Intake, and Lifestyle
The effectiveness of green tea for weight loss may depend on factors such as ethnicity, habitual caffeine intake, and lifestyle. Some research indicates that people with lower habitual caffeine intake and those of Asian descent may experience slightly greater weight loss effects from green tea . Additionally, combining green tea supplementation with physical activity and a healthy diet appears to enhance its benefits for weight and fat reduction 357.
Safety and Adverse Effects
Most studies report that green tea and its extracts are generally safe, with few adverse effects. Mild to moderate side effects have been noted in some cases, but serious adverse events are rare 12. High-dose green tea extract was well tolerated in clinical trials, with no significant side effects reported .
Conclusion
Green tea and its extracts can contribute to small reductions in body weight, BMI, and waist circumference, especially when combined with a healthy lifestyle. The effects are generally modest and may be more pronounced with higher doses or in certain populations. Green tea is generally safe for most people, but its impact on weight loss is likely to be limited without additional dietary and lifestyle changes 12345678+2 MORE.
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