Fat is a wonderful thing. It aids in nutrient absorption, hormone regulation, thermic insulation, cognitive/mental functioning, and much more. However, too much of a wonderful thing, can begin to harm us. When stored in large quantities inside our body (particularly around our waist), fat can lead to several health problems, such as diabetes, hypertension, and heart disease.
There has been much research investigating how to expedite weight loss and cure the obesity epidemic, and the answers are actually quite simple…
1. Eat a proper diet
2. Exercise sufficiently
Fat and The Magic Pill
However, many supplement companies would like to convince us that there is a magic bullet or pill that will make fat loss easy and effortless. This is a series where I will not investigate specific fat burners, rather we will explore the research and explain the main ingredients therein.
Kicking off this multi part series, I will investigate an ingredient that is often advertised as safe, natural, holistic, and healthful…you guessed it,
green tea extract!
How Does it Work?
Essentially, the mechanisms for how green tea should affect weight loss are associated with a milieu of neural and enzymatic reactions that lead to:1
- Increased Energy Expenditure. Expend more energy at rest, as measured by Calories (i.e. resting metabolism).
- Increased Fat Oxidation. Have increased usage of fat as an energy source.
- Decreased Nutrient Absorption. Absorb less nutrients from the food you eat.
- Decreased Appetite. Feel less hungry, and subsequently eat less.
What Does the Research Say?
- When coupled with caffeine (50 mg or half a cup of coffee), participants used more energy (especially Calories from fat) in 24 hours.2
- After weight loss, green tea extract had no extra benefits in preventing weight regain.3
- When coupled with a low-calorie diet (roughly 900 Calories per day), no additional weight loss benefits were observed in overweight females.4
- Habitual caffeine intake seems to influence the effectiveness of the green tea extract.5
- Decaffeinated green tea extract has been shown to promote weight loss, but with no effects on fat loss or waist reduction.6 These findings mean that participants lost either water, muscle, or some combination (was not measured in the study).
Green tea extracts appears to increase resting metabolism when taken with caffeine acutely (short-term), but this increase does not translate to pounds off the scale in long-term cases. Green tea appears to have minimal to no effects on long-term fat/weight reduction or maintenance. Any changes in body weight may occur from a suppressed appetite (we eat less), and any weight loss appears to come from mostly water and/or muscle (not fat). Decaffeinated Green Tea extract seems to be of little use, thus save your money.
However, green tea is full of antioxidants, and promotes general health through various mechanisms. So, drink it for your health, or if you just like the taste, but do not be fooled into believing that this is the magic pill that will help you drop those last couple of pounds for the beach.
2. Dulloo, A. G., Duret, C., Rohrer, D., Girardier, L., Mensi, N., Fathi, M., ... & Vandermander, J. (1999). 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, 70(6), 1040-1045.
3. Kovacs, E. M., Lejeune, M. P. G. M., Nijs, I., & Westerterp-Plantenga, M. S. (2004). Effects of green tea on weight maintenance after body-weight loss. British Journal of Nutrition, 91(3), 431-438.
4. Diepvens, K., Kovacs, E. M., Nijs, I. M., Vogels, N., & Westerterp-Plantenga, M. S. (2005). Effect of green tea on resting energy expenditure and substrate oxidation during weight loss in overweight females. British Journal of Nutrition, 94(6), 1026-1034.
5. Hursel, R., Viechtbauer, W., & Westerterp-Plantenga, M. S. (2009). The effects of green tea on weight loss and weight maintenance: a meta-analysis. International Journal of Obesity, 33(9), 956-961.
6. Basu, A., Sanchez, K., Leyva, M. J., Wu, M., Betts, N. M., Aston, C. E., & Lyons, T. J. (2010). Green tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndrome. Journal of the American College of Nutrition, 29(1), 31-40.