Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: Leah Deal on 18/10/2005 06:06:29

Title: During exercise, when does the body burn sugar and when does the body burn fat?
Post by: Leah Deal on 18/10/2005 06:06:29
Hi,
I heard on another PodCast that during the first 20 minutes of a cardiovascular workout, like running, the body is burning off only blood sugar. It is not unitl after the 20 minutes that you start actually burning fat. I don't know if this is true. However, if it is, does that mean that if you run in the morning before eating, that you burn fat sooner, since the blood sugar is probably lower?

I'd love to hear back from you. The show is great (https://www.thenakedscientists.com/podcasts)!

Thanks for all your knowledge.
From Minneapolis, MN with regards,

Leah Deal
Title: Re: During exercise, when does the body burn sugar and when does the body burn fat?
Post by: Les the Scientist on 19/10/2005 22:30:26
I read an interview in men's health magazine that said exactly that.  This guy said that he never ever ate anything before exercising because the body burns it's fat instead of the energy released from the food in his stomach.  So I say it's true !
Title: Re: During exercise, when does the body burn sugar and when does the body burn fat?
Post by: thefunkyaquarium on 19/10/2005 22:45:45
I've read that as well, in several places.  However, beware that since you're "running on empty", you won't be able to exercise as efficiently as if you ate something before the activity.

My rower friend tells me, you should eat slow-release foods before exercise (e.g. bananas, porridge) and fast-release foods after exercise (e.g. glucose drinks, jaffa cakes) for a fast recovery.
Title: Re: During exercise, when does the body burn sugar and when does the body burn fat?
Post by: Leah Deal on 20/10/2005 22:39:04
Thanks! Your remarks are really informative.

Leah Deal