This doesn't mean you should abandon your training altogether and do the usual thing of planning your New Year's Resolution, which only ever lasts a month, tops, and that doesn't begin until several days after the New Year's eve hangover, so three weeks or so and you get bored. Then, before you know it the sun comes out and you cringe looking at yourself with flesh showing .. and the flesh falling over your shorts, and... well you needed new shorts anyway ....NO!
Rewind, we are not going down that path, we are in training NOW. Drink loads of water and jog off your hangover, save the chocolate for Christmas and Boxing Day, not the weeks leading up to Christmas, make the chocolate treats special, not gluttonous indulgement. It's hard, but there is no point having a Resolution after all the damage is already done.
Resist overindulging now, Christmas is not when the shops start selling massive tins of your favourite assortments, Christmas is 25th December, and a day or so won't matter to your training. Weeks will! Even better, go for a run or a bike ride early Christmas morning and you have earned your Christmas Dinner!