3. Beware the booze. Alcohol itself has quite a few calories. Once you add mixers, the calorie count can really start to soar. Opt for pairing your booze with water, seltzer or diet soda. Choose a light beer - there are several under 100 calories per bottle. And of course, drink in moderation. The lower your inhibitions, the less self-control you may have near that cookie tray.