Researchers are looking into the potential of green tea to prevent cancer, provide antioxidant activity, enhance cognition, improve general health and well being, fight the aging process, promote oral health and…help with weight loss!
One of the simplest reasons green tea extract helps with weight loss is that it contains caffeine, and it often replaces the caffeine found in fat-burning supplements. Much quality research shows that caffeine reliably assists with fat burning. In addition, green tea extract is a powerful anti-oxidant, similar to vitamin C and beta-carotene. However, the active ingredient in green tea extract, known as epigallocatechin gallate (EGCG), may be far more powerful than vitamin C, vitamin E, or beta-carotene. EGCG stimulates thermogenesis, when the central nervous system releases fat into the blood stream for use as energy.
Another beneficial effect of green tea extract is that it regulates glucose and slows the increase in blood sugar following a meal. The mechanism behind this is the slowing of a digestive enzyme known as amylase. Amylase breaks down carbohydrates after a meal, causing a significant rise in blood sugar levels. In a recent study in the American Journal of Clinical Nutrition, green tea extract caused a slowdown in the activity of amylase.
Specifically in terms of weight loss, a double-blind study in the American Journal of Clinical Nutrition looked at Japanese men with similar BMI and waist circumferences who took green tea extract versus men who took a placebo. The men who took the green tea extract showed significantly lower body weight, BMI, waist circumference, body fat mass and subcutaneous fat than the placebo group.
Green tea may also reduce the activity of fatty acid synthase (FAS), which is a critical system involved in turning carbohydrates into fat. A study in the journal Life Sciences examined the effects of over 30 different Chinese medicinal herbs, including green tea leaf, on fatty acid synthase activity. Out of all 31 herbs, green tea leaf was one of three that exhibited FAS inhibitor activity and led to a significant increase in weight loss in rats given the herb.
Finally, we all know how important exercise is to losing weight. It burns calories, increases your energy, and builds muscle, which in turn boosts your metabolism even higher. Green tea aids in this process through its catechin phenols, which seem to stimulate the liver and muscle cells to use fatty acids instead of carbohydrates for fuel during exercise. This allows you to exercise longer, and harder.
There may be some side effects from excessive consumption of green tea in liquid or extract form. Most are related to the caffeine component, which can cause upset stomach, restlessness, irritability and sleeplessness when too much is consumed. If you are pregnant, limit caffeine consumption to no more than 300 mg per day. Certain medications can interact with green tea, and you should check with your physician before beginning to take green tea if you are taking any of the following: aspirin, adenosine, clozapine, lithium, or blood thinners. Finally, anyone with a known allergy to caffeine or tannin should avoid green tea and its extract. Keep in mind that side effects are only known to occur with excessive consumption and moderate use of green tea should have no negative effects whatsoever.
In terms of cups of tea per day, 3-5 cups of green tea per day has been shown to increase calorie expenditure by 70 to 80 calories. That may not sound like much, but over the course of a year that’s 8 pounds lost, without dieting. When taking green tea extract as a supplement, you’ll want to take the equivalent of around 200-400 mg of EGCG per day, so check the label carefully to know how much EGCG is found in your particular supplement.