The key to success for me so far has been to pack a balanced lunch each day for work. It may take a few minutes in the morning but after a week or so it blends right into your morning routine. Not going to the café at work and having to see all those foods I shouldn’t eat is a huge help. I also keep plenty of healthy snacks right at my desk that I can reach for when I do get hungry without running to a snack machine which rarely has any healthy options available.
Don't forget to have water at your side at all times too!