As I've mentioned before,
- People are not walking math formulas whereby if they have 3,500 more or less calories than they burn they'll gain or lose a pound.
- 3,500 calories of one food or type of food will likely have a different impact on health, hunger, thermic effect, and weight than 3,500 calories of another food or type of food.
- Different people have different caloric efficiencies whereby they are seemingly able to extract more calories from food or reserves than others and lose weight with more difficulty (and gain with greater ease).
From a weight management perspective, the currency of weight is calories. While exchange rates undoubtedly do vary between foods and between individuals, you'll always need your own personal deficit to lose, and surplus to gain.
But "counting" suggests upper limits or ceilings you can't crash. So too do the words, "accountability", and, "honesty" - and yet those words underscore most people's approaches with food diaries.
Food diaries aren't there to tell you whether or not you've been good or bad, how much you're allowed, or how much room is left for dinner. That said, a food diary is for information and while calories certainly aren't the only nutritional determinant of health the fact that they're imperfect doesn't divorce them from having some importance if weight's a concern. The more information you have before you make a decision, the better that decision's likely to be, and in our Willy Wonkian wonderland of food, having more information is a good thing so long you use it as only one piece of a non-judgemental decision.
I guess what I'm trying to say is that the smallest number of calories you'll need to enjoy Christmas is likely to be higher than the smallest number you'll need to enjoy today and that if your general food diary practice is to allow non-contextualized calories make you feel badly about yourself when you "go over", there's a good chance that eventually the guilt you'll feel when real life leads you to higher numbers will see you stop considering the numbers altogether.