well nuts have potassium and magnesium-which I find I have to supplement a lot as I run. I take mag citrate 500 every morning. Also, it is cliché as the epitome of race food but running with a banana is great. I am not training for a marathon right now so I don't eat while I run. I rarely get over 15 miles now. 2 years ago in ultra training I would start the run with a banana in my hand. I also like those baby food type squeeze things with sweet potatoes and fruit mixed in-really good. You can get them at REI.