Isn't the whole idea behind GORP replacing the carbs (glucose) you burn off exercising? So as your glucose levels drop, you feel tired and lack energy. So you gotta make more glucose by eating some starchy/sugary stuff. With LC you should be burning stored fat rather than blood glucose so you really shouldn't be having the energy drops you'd have if you were eating a typical high-carb diet (remember carb loading??? Tee hee).