There are so many ways to flavor your proteins this barbecue season without piling on the calories. The key is to slit your proteins to allow the marinade to absorb into the flesh and let it sit for several hours in the refrigerator.
Consider using ingredients from the following list and remember, you can use water to create more liquid:
Citrus- lemon, orange, grapefruit, etc… (you can also use the rinds)
Low sodium soy sauce- a little goes a long way
Fresh herbs- crush them to make a pulp and spread well over protein
Spices- use different combinations for different flavors each time
Sugar-free maple syrup- to add some sweetness to the protein
Other sugar-free condiments- barbecue sauce, teriyaki sauce, Worcestershire sauce, ketchup, etc…