Lipolysis vs. glycolysis

[BaconTastesGood]

For you med/science people, does anyone know the rough rate at which our bodies can extract energy (i.e. kCals/hour or whatever) with lipolysis vs. glycolysis. In theory both provide similar energy, but I've had some friends claim that lipolysis is less effective for athletes since it's rate of energy production is much lower, and thus harder for someone (without glycogen stores) to use to maintain high bursts of energy for short periods of time.

After some Googling, I can't find any information at all as to how long the lipolytic chain takes to extract energy from stored fat.

[jpinard]

Been a while since my med and organix chem classes, but extracting energy from fat involves an extra step or two (I think) which is why the body takes glucose first.

[Jon Rowe]

jpinard is on the right track here.

Lipolysis takes more energy and time to accomplish energy extraction than glycolysis. If I am correct. Lipids are more efficient at storing energy than sugars, but it is much harder to extract it.

I think... it has been a couple years since my physiology classes.

[BaconTastesGood]

You're both right, lipids have almost double the energy storage capacity of carbs, and there are a couple extra steps for lipids (fat => TG => (FFA/ketone bodies,glycerol), but while I accept that lipolysis is slower, my question is HOW much slower? I just assumed such numbers existed somewhere, but as I'm finding out about a lot to do with diet and nutrition, a lot of what we think is true is just assumption.