1g fibre: 2-3g calories and finally... 1g alcohol: 7 calories
If a drink represents 150calories, we can take this from either carbs or/and fats. For example:
Carbs - 150calories from alcohol taken off carbs (150 divided by 4) = 38 (rounded up from 37.5). For a glass of wine that provides 150 calories, this is equal to 38g carbs.
Fats - 150calories from alcohol taken off fats (150 divided by 9) = 17 (rounded up from 16.6). For a glass of wine that provides 150 calories, this is equal to 17g fats.
So lets say your daily macros are P120 F80 C150. You plan to have 2 x150ml glasses of white wine on christmas day. Each glass of wine worth 150 calories.
150 x2 = 300
300/4=75g carbs or,
300/9 = 33g fats.
So depending on your total daily macros decide which macronutrient you want to deduct from.
As you can see, it really doesn't leave you with much room for christmas pudding!
How to borrow macros:
So you know you have a big day of eating and drinking and you want to be able to track this and stay on target but you don't think you will have enough macros left over for this meal.
What do you do?
So this is where you can 'borrow' macros from another day or days.
Example you macros are P140 F70 C200. You would usually have 5 small meals.
You know christmas day at your parents is always full on and you love your mums cooking, there will be christmas pudding and wine. Even if you just had 3 meals that day and saved most of your fats and carbs for dinner you now you wont have enough to cover it.
So you can reduce your carbs and fats for 1-2 days prior. Carbs 50g and Fats 10g for 2 days before will give you an extra C100g and F20g to your meal.
Macros for christmas day would look like this P140 F90 C300.
Now all you need to do is plan your day. Start with alcohol, how much are you panning to drink and then deduct it from fats or carbs as per the calculation above.
Have a light or even skip breakfast. Personally I would eat something light, if I skipped breakfast I'm hungry and when I'm hungry I just want to eat not think about it, this equals poor decisions.
Christmas day is not a macro free day or 'F**K IT' make sure you track everything, if you still go over you can reduce your macros to cover the over spill over the next few days.
The downside of borrowing macros is that if you have more than 1 event in a span of a few days you really limit yourself.
I borrowed from 2 days prior but i still went over what do I do?
So this is where taking control of the situation and still tracking your intake comes in handy because now you know exactly how much you went over by and can do something about. Over eating and not knowing but how much, then starving yourself the next day or training excessively is not the right option here.
Lets say you went over by 50g carbs and 30g fats. You can deduct this evenly over the next 2 days, or take 1 big hit the day after and a little reduction on day 2. Make sure you update MyfitnessPal with your now reduced targets so that you don't forget and just revert to your original macros.
Stay within you daily calorie allowance.
You can also play with your carbs and fat allocation to stay within you calorie allowance. If you have for example gone over fats by 20g but have 45g carbs left one day this is the same caloric value so can net each other off.