I think you can, when I did optifast, I had a big crave for dill pickles ( no sugar, only pickles, garlic, salt and vinegar) and ask Martine and she told me no problem...
HW 320 SW 299 goal W 150 CW 138 (5' 7 " ) At Goal !!!
I asked the same question (pickles) and was told that was fine...
I'm also finding that if I steam green beans and throw steak spice on them, they're delicious even without any kind of butter/margarine!