"Made with" or "made from"

Those terms are virtually meaningless since they don't say how much of an ingredient was used or what happened to it during processing. For example, these sandwich crackers do indeed contain "real cheddar cheese," but it shows up far down on the ingredient list, after partially hydrogenated vegetable oil and sugar.

Serving size

A quick glance at the label of this trail mix shows a fairly reasonable fat and calorie count, but check the serving size. The 3-ounce package supposedly feeds three. If, like most people, you're not inclined to share, you'll wind up consuming nearly 500 calories and 30 grams of fat.

A few food makers now print "per package" nutrition facts on products such as chips or drinks that one person will often consume in one sitting—but most don't. So make sure that you always double-check.