You might be interested in this interview with Dr Steve Phinney: http://www.meandmydiabetes.com/2012...ff-volek-study/.

He tells the story of an ultra-marathon (~100 miles) runner winning a particular race while eating low carb. Several of the runners ate low carb and Phinney and his assistants were able to observe their eating before and after the race as well as take blood tests. The analysis won't be available for some time, but this is very interesting new information for those participating in low carb endurance sports.