Exercise and high protein/ low carb meals while working will do the trick. And I get off work at 7 am so I make it a point to eat nothing after 4 am.
I lost weight on a third shift job. I wonder if it was the hours or the slaughter house I was working in that zapped my appetite?
i worked night shift for over 15 years, when on a 7pm-7am shift i would not eat anything after 2am. when i got home i would eat only something small like a apple/muesli bar and then go to sleep. this worked well for 10+ years and only stopped working when i got lazy.
It's probably not uncommon for a new schedule to throw off your eating and you'll get fat .solid advice in here tho.
Are you bringing your own lunch to work? The food options available at 3 am aren't usually very good.