There are folks on this site who say that your body will adapt to a ketogenic diet for running. I think there may even be an ultra runner on this list whose body has adapted and also another woman who does ultras who does use carbs, but maybe only for races, not for training. I am trying to get mine to adapt now, because as soon as I up the carbs I gain. I've never gotten to really long runs - in training the most I do is five but I will go for more to prepare for a half marathon this fall. It is getting better and I am adapting but still kind of wonky - I just started running again after a hiatus of two months so only some sprinting and two three mile sessions. I don't know if I could do a race on very low carb. I have a 5K coming up and I am not sure if I will attempt it or not. I'm definitely slower. I would probably not attempt any race more than five miles with very low carbs, but in training I'm going to try. I will definitely let people know how it goes - for me it's all about being able to continue to lose weight while running - it usually shuts my weight loss right down.

Janine