
Originally Posted by
Lemonada8
this is not true...
with training muscles, they store more glycogen in the muscles and triglycerides than untrained muscles, the FFA's are better mobilized and more accessible to trained muscles, the muscles ability to oxidize fat increases with training, and muscles reliance on fat stores first conserves glycogen during prolonged exercise.
protein is the LAST source of energy that the body uses because
A) it only has 4 cal/ g, fat has 9 cal/g
B) the amine (NH3) group on the amino acid is hard for the body to break apart because they cannot be oxidized, then keto acids are left in the body... basically this whole process is a last ditch for energy...
C) the muscle glycogen that is stored in the muscle is for the fast glycolytic, and the fast oxidative glycolytic muscles... cardio in a HR aobut 60-75% of max HR WILL NOT ACTIVATE these muscles... cardio in that HR will activate the slow oxidative muscles, which will oxidize carbs completely, and oxidize fats...
D) slow twitch muscles use oxidative phosphorlation which will oxidize fat, because thats the only way that fat can be used for energy... oxidation...
E) if you want to get really techinical with it... a .7 of a persons RER is using 100% fat and 0% CHO... but a average RER at rest is about .78... so its hard to get a RER at .7... but a RER at .85 will use roughly 50-50 carbs/fat - so if you are in a carb defecient diet... you will have to use more fat than carbs
so you have to be WAY above a 130 HR to even begin to think about burning the proteins from the muscles... and its going to get the protein from the diet before muscle... the only time it gets protein from the muscles is in times of starvation and extreme malnutrition