Balance of Food

How much fat should a vinaigrette have? Is it zero? 2? 5? Not to pick on Wendy's, but their vinaigrette had 18 grams of fat. 18 is more per serving than any blue cheese dressing I buy, and blue cheese is normally "king of the fat." Vinaigrette certainly means, if not implies, very little fat. Water was the main ingredient followed by soybean oil. Water was first, and still it was 18 fat grams. Shouldn't vinegar come before oil in a vinaigrette? I've heard a lot about fast-food salad dressing having tons of fat. But I didn't think about it until I saw the label last night at dinner. I was being good: salad, plus burger and fries. But the dressing had more fat than any other item. To be fair, the manager handed me the nutritional info sheet. What I wanted was a light vinaigrette. Do I have to carry dressing around with me just in case I run into a salad?