I did one back in 2013 (has it really been 6 years!?!) at the age of 30 and didn't use the diet back then. The training for it alone seemed to put me in remission and I ate a LOT while training. I finished in a few minutes over 4 hours (was hoping to get under). After that I did 3 or 4 halfs over the next few years. Haven't done a race in a while but mainly due to lack of motivation. I am not sure how well NSD works with distance running but I think it can be handled with high quantities of fat for fuel.