It is a Christian custom that we fast before our feasts.
Our friends at Rorate remind us that before 1965, 23 and 24 December were days of fasting and abstinence.
May I suggest to you good readers that you do something along these lines?
Perhaps cutting back on what you eat or that you abstain from meat be taken seriously for a couple days before Christmas.
Couple the mortification with some corporal and spiritual works of mercy.