In the past two decades, the health benefits of green tea have been explored in depth, including green tea's effects on dental health, heart health, cancer resistance and brain health, but no other topic has been explored in more detail than green tea's impacts on weight. Consumed in adequate dosages, green tea can have profound impacts on metabolic rate, insulin sensitivity and weight loss.
Green Tea Basics
Green tea is made via steeping the dried leaves of the Camellia sinensis plant in near-boiling water for several minutes. Each cup contains a small amount of caffeine---approximately one-half that of a cup of coffee---the amino acid L-theanine, and a catechin called EGCG, to which many attribute green tea's weight loss effects.
Green Tea and Metabolism
Green tea can enhance weight loss efforts by providing a boost to metabolic rate---the energy you burn throughout the day while resting---with consumption of a few daily cups, says Dr. Jonny Bowden, a clinical nutrition and weight loss specialist. Green tea's primary catechin EGCG is rumored to work by inhibiting the breakdown of norepinephrine---adrenaline---that regulates the metabolism's speed. Shoot for at least three cups a day or the equivalent in supplemental green tea extract, says Bowden.
Green Tea and Fat Consumption
Fats, while healthful in appropriate quantities, can reduce the success of any weight-loss program. Research in the 2006 European Journal of Clinical Nutrition conducted by Dr. Tariku Hsu demonstrated that green tea, when consumed with meals with excessive fat content, can reduce the absorption of fat. Reducing the absorption of excess fat can reduce total energy consumption and make weight loss easier to accomplish. Reduce fat absorption with green tea by consuming green tea regularly throughout the day, especially with fatty meals.
Green Tea and Insulin Sensitivity
Green tea can improve the body's ability to tolerate meals high in carbohydrates and better control blood sugar, making it a powerful asset in weight-loss programs and especially in people displaying characteristics of poor insulin sensitivity, including increased abdominal fat and frequent sugar pangs, according to Dr. Isabelle Hininger-Favier, a nutritional biochemistry researcher. Controlling blood-sugar levels and reducing the amount of insulin necessary to store energy has been associated with improved weight loss outcomes, says Dr. Hininger-Favier.
Green Tea Decreases Fat Cell Proliferation
Regular consumption of green tea has been associated with decreased proliferation---growth and replication---of fat cells. The destruction of fat cells can help inhibit weight gain or spur on weight loss in those overweight or at risk of obesity, says Dr. Paolo Monteiro and his 2008 study in the Journal of Nutrition. Animals fed green tea throughout the day for six months finished the study with significantly smaller fat cells and gained less weight than control groups despite being overfed. Approximately two to three cups were consumed daily in Dr. Monteiro's study.
References
- "150 Healthiest Foods on Earth"; Jonny Bowden, CN; 2007
- "European Journal of Clinical Nutrition"; Polyphenol-Enriched Oolong Tea Increases Fecal Lipid Excretion; Tariku Hsu, Ph.D.; November 2006
- "Journal of the American College of Nutrition"; Green Tea Extract Decreases Oxidative Stress and Improves Insulin Sensitivity; Isabelle Hininger-Favier, Ph.D.; August 2009
- "Journal of Nutrition"; Chronic Green Tea Consumption Decreases Body Mass, Induces Aromatase Expression, and Changes Proliferation and Apoptosis in Adult Male Rat Adipose Tissue; Paolo Monteiro, Ph.D.; November 2008
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