Welcome to Part 2 of this series. So far, we have looked at ingredients used in common fat loss/weight loss/fat burning proteins and products that have claimed to block carbs, that is they are able to affect carbohydrate metabolism in some way to either reduce the amount of energy that we obtain from carbs or to shift carbohydrate storage into glycogen and away from fat.
To quickly review the evidence so far:
Effects & Dosage
Phaseolus Vulgaris (containing phaseolamin)
Hydroxycitric Acid (HCA)
In this article, we will take a deeper look at ingredients classified as ‘thermogenics’ used in these fat loss proteins and products.
Fat Burning Protein - Raising Your Metabolism
How many times have you heard people complain about their metabolisms? And with good reason; your resting metabolic rate (the energy you use up just quietly sitting) makes up around 60-70% of the energy you use all day. Add to that the energy produced through thermogenesis (heat production) and you have a substantial portion of your daily energy production. If you can somehow increase aspects of your metabolic rate, then you stand to burn more energy without having to do a thing. A couple of products have looked at several nutrients and their ability to affect your metabolic rate in favour of weight and fat loss, the most common being:
- Citrus Aurantium (Bitter Orange)
- Green Tea Extract
Citrus Aurantium (Bitter Orange) as a Thermogenic
Citrus aurantium, more commonly known as bitter orange tree or marmalade orange tree refers to the citrus tree in which the fruit it used for marmalades and liquers such as triple sec and grand marnier as well as teas such as Earl Grey. Interestingly, the use of bitter orange extract and its peel has exploded in the last 7 or so years due to the removal of ephedra/ephedrine/ma huang from over the counter sales. The extract and peel is said to be a potent thermogenic with concurrent appetite suppressant abilities and as such possesses effective weight/fat loss potential. A 2006 review1 by the International Association for the Study of Obesity looked at the safety and efficacy of citrus aurantium and the often claimed active compound of bitter orange – synephrine alkaloids. Note that bitter orange does contain compounds which are adrenergic agonists or in simpler words, they may be able to exert adrenaline like effects upon consumption including increased blood pressure and heart rate and as such should be used with extreme caution for people with high blood pressure and other cardiovascular problems. In terms of dose, it is hard to make any final conclusions, but from the studies it seemed as though citrus aurantium doses of between 300-975mg have been found to exert some effect. More importantly, the study looks at the safety dosage for the active compound in bitter orange; synephrine. While there have been suggestions that up to 120mg can be taken, ideally, 1mg/kg/day is more than enough and exceeding 100mg/day should be consumed with caution.
Guarana for Fat Loss
Guarana is a climbing plant native to South America’s Amazon basin especially in brazil. The plants fruit is commonly used in energy drinks and the inclusion of guarana in fat loss proteins and products is mostly for their caffeine content. Caffeine has been shown to have ergogenic properties during exercise performance2. In terms of caffeine consumption and weight/fat loss, there is strong evidence2 relating the use of what is known as an ECA stack (ephedra, caffeine and aspirin) and its ability to lead to significant weight loss. Caffeine has been theorised to help with weight/fat loss in 3 primary ways:
- Suppression of appetite – However, this is a transient response which may be offset by rises in cortisol with caffeine consumption leading to increased appetite later3.
- Diuretic – Caffeine is a well known diuretic when consumed in excessive amounts which can lead to weight losses as water. However, moderate consumption has shown this to not be the case.4
- Caffeine induced thermogenesis – Caffeine has been shown to slightly raise thermogenesis by 6% from baseline levels.
Caffeine in the fat loss protein may have secondary effects of improving sport performance, exercise recovery and focus.2 Furthermore, it can help to mobilise fats through increase in adrenaline. In other words, it can increase fat metabolism through its ability to increase the amount of fats in the blood.6 It is also interesting to note that one study was able to find appetite suppressing qualities from intake of guarana extract in particular.7 Regarding the dosage of caffeine for these effects, there is no single overall conclusion as to how much caffeine is required for increases in thermogenesis or for its ability to lead to weight/fat loss. Be aware however that caffeine tolerance develops quite easily, which could mean future potential beneficial effects of caffeine might only be reached with higher and higher doses, which can have cardiovascular implications as it is a stimulant.
Green Tea Extract & Fat Loss
Green tea extract has been gaining popularity over the last couple of years as one of the main supplements of choice for weight loss. In fact its popularity is so high that since 2008 it has become the 4th most common dietary supplement being consumed in the United States8 – the leading nation when it comes to dietary supplements. Green tea extract contains caffeine and a special nutrients called catechins. Several studies have shown that these catechins have the ability to cause an increase in thermogenesis9,10. Furthermore, studies looking at green tea extracts have been able to show significant weight loss with use of green tea extracts than without, even with calorie consumption taken into account. Reductions in body fat and waist circumference has also been shown.11 Overall, the evidence pointing towards positive effects on weight with green tea extract consumption is more substantial than those pointing towards a neutral or negative effect. While it is still too early to make any final conclusions, there is good evidence to suggest that green tea extract can lead to weight and fat losses. An important note however, is that the amount of green tea extract or more precisely the amount of catechin polyphenols consumed is the most important factor when it comes to successful results. Studies have generally used a high amount of polyphenols due to their generally low oral bioavailability12. Generally speaking, the more green tea extract is in the supplement, the more effective it will be. From the evidence, it seems that it is necessary to consume 90mg at the very least of catechins a day in order to benefit.
Thermogenics & Losing Fat
Increasing your metabolic rate can be done in several ways. Eating food, gaining more muscle mass or doing exercise can all increase your metabolic rate. Increasing thermogenesis or the process of heat production in your body is also a great way to increase your metabolic rate. Besides diet induced thermogenesis (the heat produced as a result of digestion), some nutrients may be able to promote thermogenesis. With fat loss proteins or products containing bitter orange extracts or bitter orange peels, remember that dosage is important as excess consumption can have negative effects. Moreover, those with cardiovascular issues should be extra wary of use of this thermogenic ingredient as it can raise blood pressure and heart rates. Products containing guarana and caffeine may have added benefits of improved sports performance, concentration and stamina. Many fat loss products contain caffeine, which can significantly add to your total daily caffeine intake leaving you at risk of developing caffeine tolerance and negative caffeine associated symptoms such as heart palpitations, shaking and irritability. As such, ensure that use of caffeine and caffeine containing supplements are cycled to ensure maximum effectiveness. If you plan on using supplements with green tea extract in them, it is nice to know that it is quite a safe supplement to use with fairly good effectiveness. On top of that, green tea extracts can offer all the benefits without caffeine so that you don’t run the same risks as using guarana or other caffeine containing products. However, it is important to note that there are different preparations of green tea extracts which have different levels of active catechins, so ensure that you pick a supplement that uses ‘dry extraction’ or ‘partly purified’ extraction processes.
To be continued… Stay tuned to the third and final part of this series which will examine ingredients classified as fat metabolisers.
_1 Haaz S, Fontaine KR, Cutter G, Limdi N, Perumean-Chaney S, Allison DB. ‘Citrus aurantium and synephrine alkaloids in the treatment of overweight and obesity: an update.’ Obes Rev. 2006 Feb;7(1):79-88.
2 Kreider RB et al. ‘ISSN exercise & sport nutrition review: research & recommendations.’ J Int Soc Sports Nutr. 2010; 7: 7.
3 Lovallo WR, Farag NH, Vincent AS, Thomas TL, Wilson MF (March 2006). "Cortisol responses to mental stress, exercise, and meals following caffeine intake in men and women". Pharmacol. Biochem. Behav. 83 (3): 441–7.
4 Armstrong LE, Pumerantz AC, Roti MW, Judelson DA, Watson G, Dias JC, Sokmen B, Casa DJ, Maresh CM, Lieberman H, Kellogg M. ‘Fluid, electrolyte, and renal indices of hydration during 11 days of controlled caffeine consumption.’ Int J Sport Nutr Exerc Metab. 2005 Jun;15(3):252-65.
5 Belza A, Toubro S, Astrup A. ‘The effect of caffeine, green tea and tyrosine on thermogenesis and energy intake.’ Eur J Clin Nutr. 2009 Jan;63(1):57-64. Epub 2007 Sep 19.
6 McArdle, William (2010). Exercise Physiology. 7th edition. Baltimore, MD: Lippincott Williams and Wilkins. pp. 559
7 Anderson T, Foght J (2001). "Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patients". J Hum Nutr Diet 14 (3): 243.
8 Sarma DN, Barrett ML, Chavez ML, Gardiner P, Ko R, Mahady GB, Marles RJ, Pellicore LS, Giancaspro GI, Low Dog T. ‘Safety of green tea extracts : a systematic review by the US Pharmacopeia.’ Drug Saf. 2008;31(6):469-84.
9 Shixian Q, VanCrey B, Shi J, Kakuda Y, Jiang Y. ‘Green tea extract thermogenesis-induced weight loss by epigallocatechin gallate inhibition of catechol-O-methyltransferase.’ J Med Food. 2006 Winter;9(4):451-8.
10 Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P, Vandermander J. ‘Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans.’ Am J Clin Nutr. 1999 Dec;70(6):1040-5.
11 Nagao T, Hase T, Tokimitsu I. ‘A green tea extract high in catechins reduces body fat and cardiovascular risks in humans.’ Obesity (Silver Spring). 2007 Jun;15(6):1473-83.
12 Scalbert A & Williamson G. ‘Dietary Intake and Bioavailability of Polyphenols.’ J. Nutr. August 1, 2000 vol. 130 no. 8 2073S-2085S