Nothing. My normal commute is 11 miles but I've been intentionally stretching it to 15 to 17 lately. I get up at 6:10, get in to work around 7:30, and generally eat breakfast between 9:30 and 11:00, then lunch around 2PM or so, ride about the same distance back, and have a light dinner, usually just a fish or chicken sandwich or something.

I used to be wiped before I got in shape, and especially when I was still drinking soda with HFCS; I found that after switching to a diet soda and therefore losing the HFCS, I no longer have massive blood sugar crashes that leave me wiped out and useless and shaking. I can eat or not, whatever.