To get rid of (摆脱) "holiday fat" is not that easy. The followings may give you some help.
Stay Active. One of the main reasons of being fat during the holidays is lack of (缺乏) exercise. Time is spent doing holiday activities such as having a big meal, watching TV and so on. These make us more tired.
Don't Starve (使挨饿) Yourself. Many people think that before taking part in a new year dinner, they should go hungry all day so that they won't get too many calories (卡路里) later on. The fact is you may be so hungry that you will eat much more.
Choose Healthy Food. For the cooks of the family, you really need to think about the ingredients (材料) that you often use and then think about how you can make the dish healthier.
Sleep. Lack of sleep not only leads to stress, it can also lead to weight gain (体重增加). Enough sleep can help you lose weight in some way. So try to have a good night's sleep.