The origin of green tea is traced back to China and there are a variety of green teas available there. But the most effective variety for weight loss is Xi Hu Longjing. Apart from weight loss, the different green teas are known to impart many beneficial effects like lessening blood pressure and blood sugar, cholesterol, heart diseases, arthritis, osteoporosis and even helpful in cancer prevention. Since historical times green tea has been used for various ailments.
The botanical name of green tea is Camellia sinesis. Compared to other varieties of tea, green tea is minimally processed and the leaves are not fermented before drying. It has got antioxidant properties. It is known to have a positive effect on weight loss. Green tea accelerates oxidation of fat and thermogenesis.
Mode of action:
Thermogenesis: In this process energy is generated at cell level. Thermogenesis is monitored by sympathetic nervous system. This process adds to the basic energy consumption and also oxidizes fat content of the body. Thus the stored body fat is used up reducing total fat content. The catechins and caffeine present in the green tea stimulate the process of thermogenesis. Catechins, especially Epigallocatechin gallate EGCG reduce the production of fatty acids in the body. Catechins also lower the body cholesterol. Catechins are a type of polyphenols. These polyphenol components of tea act as anti-oxidant and also as anti-cancer agents.
Hormone Norepinephrine breaks down the fat in the body. The extract of green tea slows down the breakdown of this hormone, thus helping in fat loss.
By research, it is proved that green tea prevents the fat present in the food being used in the body. Fats produce a protein called Leptin and this protein affects the storage of body fat. Leptin is shown to be an appetite suppressant. Now the studies on green tea extract indicate that polyphenols or catechins do act on leptin and also other hormones, which are deciding factors in appetite. All these actions combined help in checking obesity.
Along with leptin, the Green tea weight loss pills have action on Noradrenaline. This chemical acts as a neuro-transmitter in central nervous system. BAT or the Brown Fat Tissue in the body is the only type of fat that is metabolically active. When noradrenaline levels are increased, the central nervous system stimulates the brown fat tissue and the excess calories are consumed. The energy expenditure is considerably increased due to the green tea extract, fat calorie consumption is accelerated.
Generally a cup of green tea has 80 – 100 mg of polyphenols and 50mg of caffeine. These caffeine antioxidant compounds are useful in increasing the rate of burning fat.
In a clinical study conducted to check the efficacy, the green tea extract was tested on moderately obese patients for 3 months. They were given daily dose of 270 mg epigallocatechin gallate (EGCG). On an average 4.6% of body weight reduction was observed after 12 weeks. Also there were no cardio vascular side effects noticed.
The research studies have concluded that caffeine alone cannot induce the increase in metabolism rate. It was reported that the synergistic effect of both caffeine and catechins combined produced the stimulation of thermogenesis. Caffeine along with the flavonoids present in the green tea acts on norepinephrine. This is a chemical transmitter in central nervous system. This reaction on norepinephrine increases calorie consumption.
Three months studies were conducted in Japan to decide the effects of catechins (which comprise the major part of green tea extract) on body fat loss. It was found that BMI, body weight, body fat mass were reduced considerably in catechin group than in the control group.
There are also other sympathomimetic drugs, which help in reducing body fat. But those compounds exert some undesired cardio-vascular effects and increase in heart rate. But Green tea weight loss pills have no such side effects. So compared to ephedrine based diet pills, these pills containing green tea extract are considered safer options.