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Friday, June 7, 2013


The interest in fat percentage values has increased with the growing epidemic of obesity. But in the world that seeks to increase muscle mass, a concern for the best way to reduce fat has always existed.  There are many strategies that people use to burn fat in the gym and one old technique is doing cardio early in the morning on an empty stomach.

But does it really work or is it just a myth? Do you know what are the effects of exercising on an empty stomach? Can it jeopardize your training or cause opposite effects?

Most everyone knows that to burn fat you need to do Aerobic exercise. “Energy Tranformers” explained that in 2 minutes or more of continuous exercise in low to moderate intensity is needed in order to activate the aerobic system of transforming nutrients into energy with the help of oxygen. In low intensities, the triglycerides are used for Fat oxidation, but the breakdown of triglycerides in fat cells is completely prevented when there are carbohydrates available when there is a meal before exercise or supplementation of carbohydrates during. According to Bock et al (2005) the effect of Fat Oxidation that occurs with prolonged endurance exercise may depend on muscle fibre type being used, the training experience, the gender and probably diet of the individual.

This is why that for those of you who believe that doing cardio in a fasting state burns fat more rapidly are correct. 10 years ago many were non-believers of early morning exercise on an empty stomach, because not enough research existed. But this is being updated by studies proving that limiting carbohydrate availability during short term exercise can stimulate training-induced adaptations in muscle cells to facilitate oxidative energy turnover as well as fatty acid transport from fat deposits.  Doing cardio on an empty stomach after overnight fasting and absence of carbohydrate intake during the workout at a given intensity and duration depletes triglyceride levels in type I muscle fibers which upregulates oxidative metabolism in the muscle cells sparing glycogen breakdown. So energy production from fat oxidation does occur on an empty stomach to burn fat, but occurs post-exercise, and not during your workout.

Exercising on an empty stomach also has other benefits as it improves glucose tolerance (Van Proeyen, et al. 2010) and maybe a solution for insulin resistance. For something different try this because according to De Bock et al. (2007) it may present the same results when training in a carbohydrate–supplemented state. It is only not indicated for competitions because of potentially reduced liver glycogen stores and consequence of negative effect on performance.
Articles Consulted:
Carbohydrates and exercise performance in non-athletes: a systemic review of studies mimicking real-life. Columbani, Mannhart & Metter. Nutrition Journal. 2010.
Training in the fasted state improves glucose tolerance during fat-rich diet. Van Proeyen, et al. Journal of Physiology. 2010.
Exercise in the fasted state facilitates fibre type specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans. De Bock, et al. Journal of Physiology, 2005.
Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake. Bock et al. Journal of Applied Physiology. 2007.

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