
Originally Posted by
GearHeaded
a couple of reasons . to blunt Cortisol and to blunt gluconeogenisis (the hepatic conversation of proteins into glucose , and the breaking down of muscle tissue for fuel). When waking up your Cotisol levels are generally elevated (Cortisol is a hormone thats catabolic and responsible for stimulating gluconeogenisis) , and if your going to then go and do fasted cardio your Cotisol is likely going to stay elevated and your in a position to be a lot more 'catabolic' . Insulin is an anti - cortisol . it will blunt cortisol instantly (and thus yes your correct its anti catabolic)..
with Cortisol levels surpassed, gluconeogeniss is also surpressed , and when doing fasted cardio your body is not going to be breaking down proteins to make glucose for energy ,, its more likely going to begin utilizing fat for fuel
also , and this is a bit more bro science based, taking insulin before fasted cardio will help clear blood sugars that have elevated over night, and when blood serum levels of glucose are low your more likely going to oxidize more fat for fuel (assuming your doing a more lipolytic based form of cardio then a glycolytic based form of cardio)