Will we give you permission where the manufacturer will not? What is this – good cop/bad cop day?

Actually, the manufacturer of the brand you mention suggests you use "spread," because with it you can eliminate any hint of the evil trans fat. You can possibly imagine our regard for any food producer that recommends you purchase something called spread. And you have to seek out a spread labeled "0g trans fat" (since not all spreads are created equal, apparently) to reap the huge no-trans fat benefit. (Pepperidge Farm, Arnold, Bell's, and Kellogg's, at least, recommend butter or margarine for use with their stuffing mixes.)

You can make packaged stuffing without oil, butter, margarine, or spread. Add chicken stock or water to make up for the fat you are leaving out.

Remember that fat is one of the primary carriers of flavor, so your stuffing will probably not taste as flavorful as it would with the fat. Also it will not feel the same in your mouth (the all-important mouth feel) – it will be wetter ("more moist" according to one manufacturer) and will feel more doughy in your mouth.

Like anything else, it's a trade-off – no fat equals less flavor and wetter stuffing, but the complete absence of fat may be the most important point for you. Some packaged stuffing mixes recommend fairly large quantities of butter or margarine. Perhaps you'd be happy replacing half the fat with stock or water, but leaving some in to carry the flavor and enhance the mouth feel?