What about a starchy veggie or fruit. I do really well with some yogurt and a banana as a pre-run fuel. Honestly, it sounds like your body is craving something. What about salt? I know some people have a salt issue, and really need more when they are exercising more. Try this test, the next time you are feeling weak while running. Bring a packet of salt and just lick a little (kind of like you are about to take a shot of tequila, but no booze
). If it tastes really good, it is likely a salt imbalance. Try an electrolyte replacement, salt tab, or even just straight salt. I know this may sound counter-intuitive on a board and WOE that tends to deal with hypertension, and other heart problems, but, some people just burn through the salt when they exercise and sweat.