I guess my secret is that I start off my day with a run instead of a caffinated drink and that wakes me up in the morning. I drink decaf tea when I get into work, but I try to stay away from caffeine which might lead me to crash in the afternoon. I also eat food that are high in nutrients and fiber so that my body has what it needs to keep going all day long. I stay away from processed sugars and processed foods in general.
I think the combination of staying active throughout the day and eating right to fuel my body is what keeps me going. If you want an sample of what a typical menu looks like for me in a day, let me know and I will send it over!