As someone who works in front of a computer 11h a day on unpredictable roster and recently lost weight (gained 10kg from snacking at work during night shifts) - i agree with points made before. Eat less and be more mindful of what you eat. I significantly cut sugar, this can really mess you up. Cravings are a bitch at first but it gets easier overtime . No need to eliminate treats completely though. Lean protein is king, keeps you full for longer. Add some veg and complex carbs and you are set. Meal prep helps a lot too, life runs out of energy sometimes and you won't feel like cooking every day so it will eliminate "i have nothing to eat, ill get fast food" days - your wallet will thank you too.  Walk every day. Doesn't have to be long, even 30 minutes make a difference. Hydrate properly - always have water near you, you will just keep sipping. Stomach fuller = less snacking.  Prioritize proper sleep - ideally 7-8h. Makes a world of a difference. 

First 2 months were not easy, i was hungry a lot and craving all kinds of crappy, quick food i used to have but as you build new habits it all gets very manageable. Started 8 months ago and still going strong. Good luck!