A main ingredient of guarana is caffeine; there have been several studies that have shown a significant increase weight loss with caffeine (53), but there have been few studies that have looked at the nutritional supplement on weight loss. Other studies of guarana have shown an increase of energy expenditure and fat oxidation of short periods of time which suggest that this could be due to a reduction in respiratory quotient and an increase in lipid oxidation (54).
53 – White, LM,, Gardner, SF, Gurley, BJ, Marx, MA, Wang, PL, Estes, M. (1997). Pharmacokinetics and cardiovascular effects of Ma huang (ephedra sinica) in normotensive adults. Journal of clinical pharmacology. 37, 116-122.
54 – Be´rube´-Parent S, St-Pierre S, Prud’homme D, Doucet E, Tremblay A. (2001). Obesity treatment with a progressive clinical tri-therapy combining sibutramine and a supervised diet–exercise intervention. International Journal of Obesity. 25, 1144–1153.