You can do it! I've been slowly transitioning away from snacking. It's tough sometimes, but I find as long as I eat enough during meal times I'm fine.
I work in an office and sit down all day. No one's going to stop me from stuffing my face all day if I want to. In fact, a lot of people I work with do. Some of them live for food. There were free donuts in the break room yesterday and once someone discovered the fact, suddenly things got very loud all over. Some people were whispering and trying to hush others so that the donuts wouldn't disappear too quickly. It was a little bit scary the way they were reacting.
I used to be like that. Now I take pride in getting all my work done each day and that's all I need to satisfy me. Back when I used to snack all day, it would actually take time away from my work. Less snacking means more productivity for me.
If snacking is a problem for you, the best thing to do would be to really fill up during meal times. Don't go crazy, obviously, but don't hold back either. Eat as much as you need to eat to get you through to the next meal time. Sometimes I don't feel hungry at lunch, but I'll eat a small meal anyway just so I don't feel tempted to snack all afternoon. Luckily for me, I never carry change around, so I'm unable to buy anything from the vending machines on our floor. If you have vending machines where you work, I would recommend keeping the coins at home!
Good luck! :)