One of my clients is a bartender and I tell them to follow this simple protocol to stay in shape (she says she only gets good tips when she's "looking cute" haha):
1) DO NOT drink at work, and limit alcohol in-take after work. Bartenders like to stay late and drink after hours -- I try to get her to avoid this.
2) Exercise first thing in the morning. This helps rev up her metabolism for the day, and if the workout is an intense one (sprinting, fast-paced weight lifting, etc), the hormones released drastically raise her fat burning metabolism as well as keep her awake for her shift.
3) Stay away from the bar food. I have her pack food she can keep in the fridge behind the bar to avoid snacking on wings and nachos all night.
4) Approach alcohol like an expert, not a frat/sorority person. When you DO drink, drink the good stuff and only drink a little of it. If you spend $15 on top shelf stuff and only sip it, you take in a lot less calories than if you spent $15 on 4-5 beers.
Hope this helps!