where are calories taken from?

bakergirl178

I heard that it takes 30 minutes for your body to start "burning fat". i typically do a pretty good workout on the elliptical (level 11-13 out of 15, intervals) for 30 minutes. where am i pulling the energy/calories to exercise from? if i didnt eat before i worked out, shouldn't the energy come from fat? i've been doing this workout for the past month or so and i haven't really seen progress.

GetSoda

http://en.wikipedia.org/wiki/Glycogen

It sounds like what you are looking to accomplish is:

http://en.wikipedia.org/wiki/Ketogenic_diet


I doubt 30 minutes on the elliptical will fully deplete glycogen stores. Especially after you've done them for a while.
Maybe 30 minutes of hill sprints.

55in13

Think bigger. It's not about the 30 minute deficit, it's the calorie deficit over 30 days and over 30 weeks that takes the fat off.

BrianSharpe

Forget everything you've heard about burning fat.

If your primary concern is weight management all you really need to care about is total calories burned not whether they came from fat or glycogen. Generally speaking the "fat burning' zone is low intensity cardio, yes in this "zone" you burn a proportionally higher number of calories from fat but, overall a much lower number of calories.

http://www.canada.com/topics/bodyandhealth/story.html?id=1740622b-d130-486c-a4d3-f05d14878ff9

http://www.brianmac.co.uk/fatburn.htm

The only people who really need to worry about training their bodies to burn fat more efficiently are endurance athletes. Almost any one of us has enough glycogen reserves to see us through 60 to 90 minutes of aerobic exercise whereas even a skinny 140lb marathon runner has, for all intents and purposes, a virtually unlimited fuel supply by way of fat.

If you're not seeing results (which I take to mean weight loss) look closely at what you're eating, most weight loss happens in the kitchen (but don't quit exercising - it has a myriad of other health benefits)