borofergie

I'm not a decent runner by any standards, however there is a growing movement of athletes and sports scientists who are rejecting the "carb loading" philosophy.

The reason why runners often "hit the wall" during marathons is that they exhaust their muscle glycogen supplies, and have to fuel the last six miles or so with fat oxidisation. This is basically just hypoglycemia, and the transition between a glycogen burning and fat burning state is difficult in the middle of a marathon.

The alternative is to train your metabolism is operate in a fat burning state from the start. This has the following advantages:

1. You use up your muscle glycogen supplies at a much slower rate (using fat as their principle fuel supply at much higher intensity than a sugar burner).
2. You train your brain work on ketones rather than glucose, making your resistant to hypoglycemia.
3. You have limited capacity to store glycogen, but (even in the leanest athletes) and practically unlimited supply of body fat. This means you do not have to worry about in race fuelling.

The net result of this is that you should be able to avoid hitting the wall.

The approach is used by a growing number of ultra runners, including Western States Winner Tim Olson. It's based of scientific research by Volek and Phinney.

Tim Noakes, who is probably the most prominent sports scientist in the world, and the guy who literally wrote the book on carb-loading is also an advocate of this approach.

In my case it suits me, because as a diabetic I don't want to be consuming lots of "energy gels" in order to get me through the Berlin Marathon.