Surprises are great when it comes to holiday gifts. Not so much when we're talking about hidden calories that can add bulk to our waistlines. Sure, the holidays are a time of indulgence, but that doesn't mean we shouldn't know what we're eating. Thanks to copious amounts of fat and sugar, some of the greatest holiday treats are heavier in our stomachs than the packages in Santa's sleigh, with one snack providing nearly half the fat or sugar you should eat in a day. If you are on an average diet of 2,000 calories a day, you should consume no more than 65 grams of fat. Sugar consumption is a little more complex. The World Health Organization says no more than 10 percent of total calories should come from sugars. So, if we're talking a 2,000-calorie diet, adults shouldn't exceed 50 grams of carbohydrates in the form of sugar. The National Academy of Sciences Dietary Reference Intake has looser standards, saying 25 percent of calories -- or 125 grams of carbohydrates on a 2,000-calorie diet -- can come from refined sugar. No matter which guidelines you choose to follow, consider how much damage you may be doing to your diet when grazing at holiday parties. Here's what's hiding in some of the more popular goodies of the season: EGGNOG 4 ounces; 172 calories; 9.5 grams of fat; 17 grams of sugar GINGERBREAD COOKIE 1 (21-gram) cookie; 90 calories; 5 grams of fat; 6 grams of sugar PECAN PIE 1/8 of 9-inch pie; 502 calories; 27 grams of fat; 58 grams of sugar PIGS IN A BLANKET 2 pigs; 465 calories; 32.7 grams of fat; 5 grams of sugar PEANUT BRITTLE 1 ounce; 128 calories; 5 grams of fat; 18 grams of sugar CANDIED YAMS About 1 cup; 286 calories; 7.9 grams of fat; 41.1 grams of sugar Sources: AllRecipes.com; CalorieKing.com; NutriBase IV Clinical Edition; Albany Times Union research 