i was having that problem too, and the first thing i tried was eating a couple of power bars before i left work, and plenty of fruit and other goodies. that helped alot, but then i noticed a whole new problem. the closer i got to the end of the week my figertips, nose, toes, and such extremities would tingle and i wouldnt have a whole lot of feeling in them. after awhile i finally talked to a doctor about it, and it turned out to be not enough electrolytes in my system. thats when i learned how important lemon water and sports drinks really were. that also made me feel like i had more energy. so that may be something to try.