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!?

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.

When calculating the carbs, calories, and fat of a marinade used for grilling, the key is to account for what actually ends up on your food—not just what’s in the bowl. Start by adding up the nutritional values of ajustar dispositivo de gravação no Windows 10 every ingredient in the marinade (oils, sauces, sweeteners, spices, and acids like vinegar or lemon juice) using the nutrition labels or a reliable database such as USDA