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When do we burn only dietary fat?

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  • #16
    Hi Guys,
    Basic biochemistry says we do need some carbohydrate to burn fat. There are two biochemical cycles involved. First Glucose is oxidized to pyruvate where ATP (the enegry currency of the cell) is made. We need ATP (Remember ultra-low carbers that gluconeogensis may occur from amino acids and protein-you can make glucose from protein). Fatty Acids are broken down to Acetyl-CoA. Both the endproducts of glycolysis and fatty acid metabolism are used in the citric acid cycle. This happens in normal fatty acid breakdown in the mitochondria. The citric acid cycle is imporatant because in the citric acid cycle NAD is returned to NADH. Since this is the thumbnail version of this, rather than a biochem course, NADH is required for a number of other biochemical reactions in the body, one place it is used is in the mitochondria to produce more ATP. If there is no carbohydrate, we will not make the ATP we need to provide energy for things like muscle contraction. A lack of ATP makes muscle contraction impossible. Ketosis is fatty acid breakdown in the liver in the absence of carbohyrate and CW also infers starvation or reduced caloric intake and is an alternate pathway. Ketone bodies can be broken back down to acetyl Co A and used in the citric acid cycle. But is the kicker...if there is no pyruvate from glucose (carbohydrate metabolism) we can't use this ketogenic acetyl-Co A to make energy in the citric acid cycle. There are more branches and sub-branches to all these this not complete... but...I hope this helps. But it is very complex and hard to just find one switch that turns everything from the use of one type of metabolic fuel to the other.


    • #17
      When do we burn only dietary fat

      Justavian wrote:ve2vlc wrote:...just relax...and alway think twice when not gaming, before take a decision...