A review of randomized controlled trials found green tea extract supplementation was associated with higher fat oxidation during exercise and recovery, though researchers said it should support—not replace—healthy habits.
By yourNEWS Media Newsroom
Green tea extract may help the body burn more fat during exercise and continue that effect after physical activity ends, according to a new meta-analysis of randomized controlled trials published in a peer-reviewed nutrition journal.
The analysis pooled data from nine randomized controlled trials that examined the effect of green tea extract on substrate oxidation, the process by which the body uses carbohydrates and fats for energy. Researchers found that participants who consumed green tea extract had significantly higher fat oxidation during exercise and in the post-exercise recovery period compared with control groups.
The findings add to research suggesting that compounds in green tea, particularly catechins such as epigallocatechin-3-gallate, or EGCG, may influence metabolism by shifting fuel use toward fat. Earlier studies have also found that green tea extract can increase fat oxidation and improve insulin sensitivity in healthy young adults, according to reporting by Mercola.com.
Researchers in the new meta-analysis reviewed studies that measured fat oxidation and carbohydrate oxidation during exercise and after exercise ended. The analysis also examined whether higher doses of green tea extract produced stronger effects.
Participants who took green tea extract burned more fat during physical activity and continued to show elevated fat oxidation during recovery. Researchers also found that carbohydrate oxidation decreased after exercise in the green tea group, suggesting the body relied less on carbohydrates and more on fat for fuel.
A prior study involving 12 healthy men found similar results. In that study, participants performed a 30-minute cycling session before and after taking green tea extract, with researchers reporting increased fat oxidation during exercise, according to Mercola.com.
Research cited in Manfred Lamprecht’s book “Antioxidants in Sport Nutrition” also reported that green tea extract altered fuel use during exercise. The book referenced a 2011 study by Ichinose and colleagues that examined endurance training combined with green tea extract supplementation and found changes in substrate metabolism in humans.
The findings are tied to the broader concept of metabolic flexibility, or the body’s ability to switch efficiently between burning carbohydrates and fats depending on energy needs and availability. Researchers consider metabolic flexibility an important marker of metabolic health, while impaired flexibility has been linked to insulin resistance, poor blood sugar control and higher risk of chronic disease.
Green tea compounds, including EGCG and other polyphenols, are known to affect energy metabolism. Michael Greger’s book “How Not to Diet” cited studies showing that green tea supplementation affected body weight, lipids and lipid peroxidation in obese subjects with metabolic syndrome. The book “The best kept secrets to healthy aging” also lists support for healthy metabolism among the benefits of drinking green tea.
Other research has examined tea polyphenols for their potential prebiotic effects and their role in how the body processes fats and carbohydrates, according to NaturalNews.com. While the new meta-analysis did not directly measure weight loss, researchers said improved fat oxidation may support better metabolic efficiency.
The dose-response portion of the meta-analysis found that higher doses of green tea extract were linked to greater increases in post-exercise fat oxidation. The researchers did not identify a specific optimal dose, but the pattern suggested a possible dose-dependent relationship across the amounts used in the trials.
More research is needed to determine precise intake recommendations for athletes and the general public. Researchers also noted that supplement quality and standardization may affect results.
Green tea extract is popular among some active adults because green tea catechins may support endurance and fuel efficiency, according to NaturalNews.com. However, researchers cautioned that the extract should be treated as a supporting tool rather than a primary intervention.
The metabolic effects identified in the review occurred alongside exercise and should not be viewed as a substitute for physical activity, a nutrient-dense diet or other core lifestyle practices.
Researchers said the foundation for long-term metabolic health remains regular strength and cardiovascular training, adequate protein intake, quality sleep, stress management and a healthy diet. Green tea extract may provide a modest added benefit for people already following those habits.
NaturalNews.com has also noted that tea is not a quick weight loss solution, but may support weight management when combined with diet and exercise. Greger’s “How Not to Diet” similarly referenced research showing green tea supplementation can affect body weight and lipid profiles within the context of broader dietary changes.
The authors of the meta-analysis concluded that green tea extract may be a useful adjunct for people looking to improve fat utilization during exercise. Still, they emphasized that daily habits remain the primary driver of lasting metabolic health.
Source: Natural News
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