How does one calculate Carbs/Calories/Fat of Marinade when grilling?
 

I often throw about 10 chicken breasts in a ziploc bag and make a homemade marinade of Light Zesty Italian Dressing, Cayenne pepper, ground black pepper, crushed red pepper, Red Tobasco and Green tobasco. I love it and can eat it for every meal which is nice (I am a simpleton).

I am left wondering how to calculate calories/carbs/fat from the marinade itself.
I always just throw the whole bottle of dressing in the marinade and the chicken soaks in the mixture for a day. I don't re-apply marinade really once the chicken is on the grill so when done, the Ziploc is still full of the marinade.
Should I not count any carbs, fat, etc. from dressing? Does it "burn off"?

Pour off the remainder of the marinade into a measuring cup. Subtract that quantity from the original quantity of dressing (16, 24, or 32oz) and enter the difference into your log.

Do that a couple of three times, and you'll have the data needed to create a custom 'Marinated Chicken breast' to FitDay.

Sure, but a ton drips off in grill and some certainly burns off.

Wow! A whole ton!? :D

Really, how much drips off? Guessimate it. A tablespoon? a couple of teaspoons? Subtract those.

The oil in the dressing keeps the meat moist, that counts. (Google 'oil smoke point')
The charring part of 'burn-off' is sugars (carbohydrates) caramelizing. That counts, too.
The smoke part of the 'burn-off' is water turning into steam, ignore it. No calories, no nutrients, and besides, you're not consuming it.