My advise: don't get ridiculous, because "FREE" salad dressing tastes like crap.
You do NOT need ranch or 1000 island or creamy italian dressing on a salad. You don't need to pile up cheese or fried chicken chunks either.
BUT if you don't have a little oil or creamy stuff, there's no point in eating a salad because it will taste terrible.
People who suggest things like Free dressing (yes, i mean fat free) or salsa or non fat yogurt just don't seem to have any taste buds.
Like some of the posts above, Yes, they will have hardly any calories, but you WILL NOT enjoy them, and you will also not benefit from any healthy caloric intake.
(strictly my opinion, but still the truth!)
And for me, eating any salad, big or small is going to be way better than most meals I eat. So seriously, you HAVE to eat. Enjoy your salad, enjoy your calories, eat your veggies, but like all things, don't over do it, or you'll get tired of eating salad all together.
Count your calories. Lettuce has pretty much zero calories anyway, so everything you add is what's going to make you fat. If you have 200 calories from italian dressing, and 200 calories of sliced turkey, you've got a pretty good sized salad, that will still fill you up and only 400 calories.
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Seriously, maybe that's how some 70 lb. underweight teenagers eat, but trying to substitute every last teeny bit of fat seems ridiculous to me. You gotta live, so eat.