The weekend is a great time to unwind and celebrate successes from the week that has passed. But if your goals are to lose weight be careful as one miscalculated meal could completely undo all your progress for the week.
 

Remember it is still total calories that matter. Even if you believe you are diligent throughout the week, letting loose on the weekend without being mindful of your food and drink can destroy all your progress. That doesn't mean you cannot enjoy, just be aware of what you are doing and plan ahead.

For tips on how to stay on track try to get more nutrient dense meals earlier in the day to allow you more calories to play with at night. Stick to lean proteins and lots of greens.  These will make you full without sacrificing those party calories.  When going out at night the obvious things to watch out for are commonly known high calorie items like desserts and alcohol. No one is saying you cannot have them just be accountable for it.
 

Weight loss is never linear so weekend mishaps will lead to an endless cycle of frustration and will ultimately cause you to quit. Understand your body, know it's limits and eat and drink within those limits consistently and you will eventually see progress.