Nothing wrong with eating at work to keep your energy up if you have a physically taxing job. (In fact the paradox of what you're trying to accomplish is that all the exercise will make you hungrier at first.) Try substituting bananas, apples and/or nuts (or some trail mix with nuts and dried fruit). These things are very dense and will fill you up, but also have a lot of nutritional value. And, since chocolate bars are exceedingly tasty, have one a once or twice a week too (alternate the healthy and "sinful" days). Eating should still be fun, after all, and as long as you maintain the equation calories out > calories in, you'll be fine. At some point you will have lost all the weight you care to (and will have redistributed it to where you want it to go) and then you just have to maintain calories in = calories out.
I had knee surgery 3 months ago, and my "calories out" plummeted due to the forced inactivity. So, I had to be extra careful with the calories in (still gained 3 pounds!) Now I am back to exercising daily and am glad of it.
Good luck!