I'm reading Slow Burn by Stu Mittleman. Stu as a record holder for 6-day races. Yes, that means he runs non-stop for six days. He trains on a hi-fat, hi-protein diet. The book stresses running with a heart rate monitor. The goal is to never run so fast that the heart rate becomes elevated. When that happens, the body is using glycogen (stored carbs). It's been my problem for a long time: I try to run fast and always fail. The lower amount of carbs in the muscles of low-carb eaters means once you use up the carbs, there's nothing left to run on.

By following the book's recomendation, I am able to run without crashing. Over time, I should get faster while staying away from carbs. The process of turning into a fat-burning runner can takes several weeks. So far I've been able to run an hour a day without problems. In the past I've done 50-mile races on a low carb diet but typically I eat carbs while running. According to Mittleman, that shuts down the fat-burning system. I have races planned this Spring and Summer.

LOL I can walk and my heart is elevated. I jsut started running... well jogging, I can do a mile but let me tell you my heart is pumping like mad.... How do I get that to stop going so fast?

I am also reading this book and have read other articles like it. I would clarify the elevated heart-rate comment. Stu reccomends keeping your heart-rate at an aerobic level without going anearobic. You burn fat in the aerobic zone, but burn glucose in the anaerobic zone. You store enough fat to run marathons but only enough glucose for about 20-30 minutes of anaerobic activity, unless you take in more glucose (carbs). I am an endurance cyclist and I can do 6 hour rides on zero carbs days before, during, and for days after. The body can run better on fat burning than carb buring of you train properly! The key is to train right near your aerobic/anaerobic treshold and gradually work it higher. Heart rate monitors can help a lot.

I'm glad to have seen these posts: endurance exercise while low-carbing was going to me my next question!

I too am a cyclist and enjoy doing long rides (century+) especially during the summer and fall (but I do them in the winter too!), but have never attempted such without eating lots of carbs during the ride.

But I am interested in resuming some distance running, too like I used to do. So I'm interested in resources and information on that topic. I'm thinking that just following a slow, moderate marathon training program with very gradual distance increases, without using supplements (like powerbars, etc) is the way to go, and to perhaps do my mid-week runs a little more aggressively.

Anyone manage to do a marathon with NO food intake during the run? Or do you consume low-carb foods?

Well I'm training for a marathon, and let me tell you I am not afraid to take in carbs before my long, 16+ mile runs. I take clif shot with me. I just did an 18 miler, the night before I ate half a sweet potato with some turkey breast, in the a.m. I ate some oatmeal, ate a clif shot about mile 9 in preparation for the "bonk". All in all it wasn't a whole lot of carbs, but enough to really help me as I was feeling very depleted/exhausted in the days leading up to the run. I kept my dietary fat low in those higher carb meals to help the carbs go right to my muscles. Often I might eat a banana before a good long run, at least 9 miles. the rest of the time my eating is low carb, high fat.
I was able to recover from this run much faster than in the past wtih no carb intake.
I can run shorter distances on no carbs, about 7-8 miles/day but any longer and my leg muscles just become really depleted and performance suffers.

I stay low carb (<25 gm/day) before, during and after bike marathons and my father (now age 65) has been running marathons for decades and never eats anything during runs, only water. What I understand is that if you let your body rely on glucose (carbs) then it will always want glucose. Unfornately, you can become dependent on that glucose. If you train your body to run on fat-burning, you can get down to some really low body-fat percentages (even as low as 4%) and still have fuel to spare.