As I told you here, I am experimenting with glycogen depletion on my long runs. Why? Well, as Laura explained here, the theory goes that when you fuel during your long runs, you deprive your body of the ability to tap into fat stores for energy. And even the leanest of the lean have lots of fat stores from which to draw energy. Glycogen, on the other hand, runs out before too long.
So–if you’re running a marathon, it behooves you to tap into your fat stores for energy. This doesn’t mean that you don’t fuel in a marathon, or that you don’t fuel during any of your long runs leading up to a marathon. But if you can first teach your body to use fat for fuel, then hopefully you won’t hit a wall in a goal marathon.
When I first read about glycogen depletion long runs, I thought, “there’s no way I can do that.” But after checking in with some trusted sources–Jeff Guadette, Dr. Mark Cuccuzella, and Jason Karp–I became convinced it was worth a try. I’ve now done a 16 and an 18, both handled a bit differently, in a glycogen depleted state. Here’s how they went and where I go from here:
Anyone else out there trying this? Or does it sound insane?