Eating healthy while working 2nd shift

I just recently started getting back into exercising however I am fnding it really hard to eat right while working 2nd shift. My 8 hours are pretty much spent sitting at a desk, with the exception of 2 10 min breaks at 4pm and 9pm with a 30 min.dinner break thrown in anywhere between 6-7pm. I guess for me, it's the convenience factor of going to fast food places the majority of the time before work to eat because it's an easy solution. Also, on my dinner break, I don't really eat a 'meal' ala a handful of cheeze-its, a stick of string cheese and a granola bar. I am not overweight but I am just trying to silm down and with being in a seditary job and predominately seditary lifestyle after graduating college, my weight as went up a bit. Does anyone have experience with working 2nd shift, if so, how do you maintain a healthy lifestyle of eating.