Spot msucle burning (fuel) - can it happen?

[9nines]

Here is a question I wonder about, but to which I have found no answer:

 

First, I know spot training for specific area fat loss (examples, crunches to lose fat around mid-section) has been proved incorrect (cadavers with unsymmetrical muscle mass - maybe more muscle mass on the left arm than right - were studied and while one limb had materially more muscle mass the body fat was the same on both limbs) but what about muscle burning from local efforts.

 

The body stores sugar in two places. Small amounts around all muscles (for short, quick, intense muscle reaction) and dense amount in the liver (only piece of meat with material amount of carbohydrates, by the way.)

 

My question, after you deplete that local sugar store (say you sprint and deplete the local sugar around your leg muscles) will your body then burn those muscle materially, even if your liver and blood still have much sugar?

[lmmy]

Warning: this is hearsay. Do not take it immediately as truth.

 

Anyways, a trainer at my local gym says that if your heart rate's over 170 at the time you run out of glycogen (which should take a while -- you have 600 grams of it stored away, after all!), you start burning muscle.

 

However -- I've heard other places (science classes, for example) that muscle is the last material that your body will cannibalise for energy. Fat comes after glycogen. Your body can synthesise carbohydrates from fat for your body to use, but although I know it's the preferred source for your brain and liver, I don't know if this is so for your muscles -- it appears so, as many of the most successful athletes are on vegetarian and vegan diets.

 

One thing though: something about the synthesis of this carbohydrate from fat can produce mild acidosis, and it can be severe and even fatal on Atkins-like diets. So if you don't want to feel really sick and woozy, don't go for long fat-burning stretches like this.