Don't fall for the "Fat-Free" trap on packaged foods. Though they may be lower in fat, it doesn't mean they are lower in calories! Most of the time, companies substitute by adding extra sugar to the product to give it a better taste that was lost from removing the fat.
Another thing to remember is that, companies are allowed to say their product is "fat-free" as long as there is less than 0.5 grams of fat PER SERVING. So, if you are eating two servings, you just consumed 1 gram of fat. Keep that in mind!
And, I'm sure you guys know it's best to stay away from trans fat.