The primary reason we need to eat food is to provide fuel for the body. This fuel comes from the breakdown of carbohydrates, proteins, and fats. To explain it simply, food is broken down to produce energy, and it takes many chemical processes for that to occur. Molecules are removed, heat is produced, but basically all that is left in the end is water, carbon-dioxide, and energy.
But it's far more complicated than that. Carbohydrates, proteins, and fats, each get converted to energy but each take a different path.
Before I start on how fat is burned (or broken down), let me first explain a few key terms in the process of converting food to energy:
Step 1: The break-down of triglyceridesTo be used for energy a triglyceride needs to be broken down into its basic units: one molecule of glycerol and 3 molecules of fatty acids. This process is called Lipolysis.
Step 2: Conversion to acetyl CoAAlthough they both have the same outcome, the glycerol and fatty acids each follow a different path. Their goal is to enter the Krebs Cycle, but first they must get converted to acetyl CoA.
Step 2a: Glycerol to acetyl CoAGlycerol, which is a basic sugar, follows the glycolytic pathway (glycolysis). During this process it is converted into pyruvic acid. For entry into the Krebs Cycle, the pyruvic acid must be converted to acetyl CoA.
This is done in 3 steps:
Step 3: The Krebs CycleAt this point both the glycerol and the fatty acids have been converted to Acetyl CoA and are now ready for the Krebs Cycle. As the Acetyl CoA is broken down, carbon-dioxide and hydrogen are removed. Once again the carbon-dioxide exits the body via the lungs. However, the hydrogen moves on to the final stage.
Step 4: The Electron Transport ChainThe Electron Transport Chain is the final process in the break down of food. Each of the hydrogen molecules that were removed during the previous processes have been transported here. They now combine with oxygen to form water (H20), with the resulting energy from this reaction causing the formation of ATP.
Ray Kelly is an Exercise Scientist with 15 years experience in the Health and Fitness industry. Sign up for his free 7 Day Weight Loss Course at: Heart Attacks, Diabetes, and Weight Loss
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