a standard lettuce salad with a few veggies (carrots, tomatoes, etc) is fine. its extremely low carb/calorie. its the dressing that sorta screws you up...especially 'fat free' dressing since its loaded with sugar, usually in the form of high fructose corn syrup (arguably the WORST man made sugar in existence).
I would make a vinegrette from olive oil and some vinegar, with some spices added. get some good fats, and skip the bad fat-free dressing.