Weight loss is often reported as a potential health benefits of green tea, but what is the science behind it? We delve down to really understand how this works in your body, how much to drink and even when to drink matcha to get the best effect….
There are two key elements to green tea, caffeine and the plant chemical catechins, particularly one type of catechins called epigallocatechin gallate (EGCg), that have shown benefits in terms of fat burning and overall weight loss.
Caffeine’s main benefit in terms of weight loss is that it has a thermogenic effect on the body. Thermogenesis is a metabolic process during which your body burns calories to produce heat. Thermogenesis can promote weight loss because it increases your body's calorie burn. Another important element to weight regulation, is Leptin which is your satiation hormone, which regulates when you're hungry. Caffeine intake (more than 300mg per day) has been shown to reduce the amount of leptin, especially in women1. Ordinarily, a lower level of leptin might make you hungrier. However, as Leptin is produced in fat cells, lower levels, indicate fewer fat cells. In addition, as people put on weight they often develop high levels of leptin due to leptin resistance. So, the body over produces and it no longer has the desired effect in terms of regulating hunger.
Caffeine has also been shown to enhance fat burning and performance during exercise2. So if you have your caffeine fix before you workout you are likely to get a triple whammy of benefit in terms of fat burn.
There is a down side to caffeine, as it also stimulates the release of cortisol, a stress hormone. If you are chronically stressed emotionally or physically this can have a negative affect on the body including hording of fat especially around the belly, as well as poor sleep, cravings, fatigue etc. Green tea is a preferable method to consume caffeine as it also contains a calming amino acid called L-Theanine, which calms and works against any stress response.
The catechin EGCg, is the other major factor in terms of green tea's weight loss potential. A recent study3 by Anglia Ruskin University, gave green tea extract with the caffeine removed, to test EGCg individual potential. The results showed that the green tea extract group reduced their body fat by 1.63 per cent, compared with those in the placebo group. Meanwhile fat oxidation rates increased by 25 per cent. This is important because fat oxidation aids weight loss.
Also the 14 volunteers were asked to cycle for one hour, three times a week. Those taking the green tea extract noted their performance increased by 10.9 per cent over a four-week period, increasing the distance they covered from an average of 20.2km to 22.4km.
One issue sited with this study was the number of the cups of green tea, 6 or 7, needed to get the recommended dose of 400mg of ECGg. However, matcha is made using the whole plant and contains higher levels of ECGg. 1g matcha contains approx. 61mg of ECGg. I use ½ tsp or approx. 3g in my matcha latte, so it contains roughly 183mg EGCg. So you do the math….2 cups of matcha or if you are more sensitive to caffeine, 1 matcha with 3 cups of decaffeinated green tea would easily get the amount you need to see the benefits.
However, one of the most interesting things about green tea and its effect on weight loss, is that studies1,4 show the combined effect of caffeine and EGCg is greater than the sum of its parts. However, this is can be affected by your current weight, your current caffeine intake and ethnicity. If you have a low caffeine intake to begin with and are of Asian not Caucasian ethnicity, then the results are likely to be more pronounced.
Practically speaking, drinking 2 cups of matcha day definitely has potential to help you loose weight and maintain it, not to mention all the other health benefits it confers. For me it’s a nobrainer!
Libby Limon BSc NT mBANT