Health Benefit of Green Tea – Obesity and Green Tea

By John E. Jernstad
Mount Kisco, NY

Obesity

Few issues capture both medical and public attention as obesity. Widely associated with various illnesses as well as higher mortality, obesity may account for as many as 15 to 20% of deaths resulting from coronary heart disease and a whopping 65 to 75% of new cases of type 2 diabetes [1], and is blamed as a major culprit for myriad other disorders, respiratory illnesses, and even some types of cancer. In 2008, 66%, or fully two-thirds, of the United States population, was found to be overweight with approximately 31% of American adults being obese. In the same year 32% of children were overweight with 17% children between the ages two and 19 being obese [2].

The most fundamental principle of weight loss is simple: eat less, move more. However, a growing body of research indicates that green tea can be a powerful ally in boosting the metabolic process to give you an extra boost in your daily regimen of healthy eating and moderate exercise, as well as a lifestyle choice that can help you prevent and suppress weight gain.

Green Tea

First cultivated in China over 4,000 years ago, Green tea has long been used in all over Asia both as a beverage as well as a method of traditional medicine to aid in everything from controlling bleeding and helping heal wounds to regulating body temperature and blood sugar, helping with digestion, and focusing the mind and body. Clinical research continues to shed more light on these and heretofore unknown heath and medical benefits of green tea.

How does green tea help with weight loss?

A large number of studies and clinical trials are shedding light on green tea’s ability to increase your body’s metabolism and specifically prevent the buildup of blood sugar and body fat. Green tea speeds up the burning of “brown fat”, a type of fat whose primary function is to generate body heat in humans by drawing calories from normal (“white”) fat to burn it. Green tea also sends glucose, the sugar from foods that is absorbed into your bloodstreams, to muscles to be used for generating energy rather than to fat tissue. Green tea also reduces the action of fat-digesting enzymes to reduce the amount of fat the body uses from the food you eat. The active ingredients in green tea have also been found to lower the body’s production of fatty acids, blood fat and cholesterol.

Growing body of evidence for green tea as obesity fighter

A study in 2005 showed that the daily consumption of green tea over a period of 12 weeks led to a significant reduction in body weight as well as waist size and body fat accumulation [3]. A group drank a bottle of green tea containing 690mg of catechins, while another “control group” drank tea containing only a small amount of catechins (far less than normally found in a cup). At the end of 12 weeks, the group that took the larger amount showed significant decreases in body weight, BMI, waist circumference, body fat mass, and fat found under the skin. A larger study in 2007 involving 240 volunteers confirmed the results of the earlier study [4]. Another study in 2009 involving 132 overweight or obese women over a period of 12 weeks showed a marked reduction in abdominal fat in the group that consumed green tea [5].

Another study in 2000 showed that a green tea extract could increase around-the-clock metabolism (“energy expenditure”) and fat breakdown thanks to its caffeine and catechin polyphenol content. Under strictly controlled circumstances, three groups of volunteers were given tea extracts and caffeine, just caffeine, and a placebo containing no active ingredients, respectively. The results showed clearly that those who took the green tea extract saw a marked increase in their metabolism, while the group that only had caffeine didn’t show the same increase in daily energy expenditure [6].

What about the caffeine?

Many people worry about increasing their caffeine intake by drinking several cups of green tea each day. Caffeine, a much-maligned substance, does in fact have several invigorating effects that fight sleepiness, speed up heart rate, increase alertness, and improve athletic performance. Of course, moderation is the key—excessive caffeine can make you nervous, irritate, unable to fall asleep, and cause dizziness and headaches in some people. Everyone’s different, but most doctors recommend limiting caffeine to less than 200 to 250mg per day. Fortunately, green tea contains about 20mg of caffeine per cup, about half that of black tea (around 40mg) and a fraction of that found in drip coffee (a whopping 90 to 150mg) [7]. In addition, the tannin and L-theanine found in green tea work together to decrease the effect of caffeine on the body while providing a host of other positive benefits.

Why choose green tea?

Walk into any health food store and you’ll be greeted with rows upon rows of supplements and nutrition aids that all seem so promising. So why should you choose green tea as part of your healthy lifestyle?

Green tea and its component substances have a positive effect on human health and metabolism, and it’s all natural. Green tea is not invasive, and doesn’t change the normal metabolic pathways of the human body or attempt to add or subtract anything that doesn’t belong there. Polyphenols, a large group of substances which includes flavonoids such as the catechins found in abundance in green tea, are present all over nature in a wide variety of plants and plant-derived food including berries, olive oil, chocolate and coca, coffee, pomegranates, fruits and fruit drinks, and numerous other vegetables. In addition, organic green tea is widely available, reducing the dangers of pesticide exposure that can be amplified by the nature of the tea-brewing process, when chemicals can leech into the water while the tea leaves (which are directly exposed to pesticides during cultivation) are immersed in hot water.

With rising awareness of the greater dangers of obesity and more people turning to healthful lifestyles and sensible food habits to lose weight and keep healthy, green tea that is rich in beneficial substances can be a powerful ally in combating obesity and maintaining a healthy body composition. Drinking green tea, combined with healthful eating habits and exercise, is a sustainable and natural lifestyle choice for anyone seeking to become and stay fit and healthy.

References

1. Kopelman, P.G., I.D. Caterson, and W.H. Dietz, Clinical obesity in adults and children. 3rd ed2010, Chichester, West Sussex ; Hoboken, NJ: Wiley-Blackwell. x, 502 p.

2. Flegal, K.M., et al., Prevalence and trends in obesity among US adults, 1999-2008. JAMA : the journal of the American Medical Association, 2010. 303(3): p. 235-41.

3. Nagao, T., et al., Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde-modified LDL in men. The American journal of clinical nutrition, 2005. 81(1): p. 122-9.

4. Nagao, T., T. Hase, and I. Tokimitsu, A green tea extract high in catechins reduces body fat and cardiovascular risks in humans. Obesity, 2007. 15(6): p. 1473-83.

5. Maki, K.C., et al., Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults. The Journal of nutrition, 2009. 139(2): p. 264-70.

6. Dulloo, A.G., et al., Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. The American journal of clinical nutrition, 1999. 70(6): p. 1040-5.

7. Chin, J.M., et al., Caffeine content of brewed teas. Journal of analytical toxicology, 2008. 32(8): p. 702-4.