T Nation

Cardio and Depleted Glycogen Levels

Hey Thibs and TNation.

I have heard multiple opinions about cardio in the morning right away on a empty stomach for more fat loss because of depleted glycogen levels in the morning.

I have also heard that there isnt much difference if you were to do it at any other time?

I read an article by layne norton where he said that it doesnt matter if you do cardio after a meal vs. on an empty stomach. His argument was that yes your glycogen in your muscles will not be depleted if you have a small meal in the morning then cardio, but your body also stores glycogen in the liver and those levels will still be low and and will be affected also, and with energy from your meal you will be able to perform cardio more intensely and burn more fat.

I was also curios if there is a difference from this and doing cardio right after a lifting session, maybe having a protein shake and some bcaa’s in the gym after then do your cardio? or what would be your thought with the post workout carbs?

SInce there is so much debate on this topic out there, lemme know your guys take on it, and would love to know what Thibs thinks!

Fasted morning cardio: Breaks down fat, breaks down muscle (yes, your body has been chewing up your precious skeletal muscle all night and will keep doing that if you don’t eat something when you wake up)

Cardio after eating: “Doesn’t break down muscle”, breaks down some fat, breaks down glycogen and food

It depends on your goals.

I don’t understand why he had to bring in the liver, and I’m not so sure he does either.

A lot of people swear by fasted morning cardio, but I’ve never been a big fan. Then again, I absolutely hate slow, steady state cardio with a passion. In my world, explosive, intense “cardio” requires carbs and bcaas.

That being said, I’m interested to get Thibs’ take on this one…

Ya im not sure if there is a better way, it seems that it is just what someone prefers

Layne Norton has some interesting theories, Thought he might have some idea to what he’s talking about with the whole liver thing since he has a PhD in nutritional science I think, but there again everyone’s body is different so who knows haha

It’s not because of depleted glycogen levels, it’s simply because you have no food in your small intestine releasing energy into the system, making the body use mostly stored fat as energy.

Even with full glycogen stores you will still burn fat if your intensity is low.

Ya I understand that any type of cardio will burn fat, but I was just curious to what type taps into fat stores at a faster rate/quicker.

My conclusion from all this: whatever method makes you able to work as hard as possible as often as possible will work best for fat loss. Being fasted or not is not that important. I am not sure if you will lose muscle mass by doing fasted cardio. I guess it won’t be significant.

[quote]Mitch08012 wrote:
Ya I understand that any type of cardio will burn fat, but I was just curious to what type taps into fat stores at a faster rate/quicker.[/quote]

Under 80% AHR. That is, during the cardio.

Over 80% AHR, mostly glycogen but fat after. Both are good, and the strength of slow steady state is that you can do ALOT of it, walking fast etc, while the intensive training, being more effective, is much more limited. You can’t do 60 minutes of true HIIT and not die.

By the way…whats the new word on placing cardio in a growth phase, for example I,BODYBUILDER, etc. Couple days of steady state or HIIT Sprints? How much is too much if lifting 3-4 days per week.

[quote]Amonero wrote:
It’s not because of depleted glycogen levels, it’s simply because you have no food in your small intestine releasing energy into the system, making the body use mostly stored fat as energy.

Even with full glycogen stores you will still burn fat if your intensity is low.[/quote]

Correct.