For many people, a Christmas or Thanksgiving meal isn't complete without a pile of fluffy mashed potatoes drizzled in savory gravy. Although you might ignore your meal plan on such holidays and indulge in this calorie-rich side dish, knowing roughly how much of a calorie punch these foods pack can give you extra incentive to lace up your running shoes the next morning.

Potatoes have a moderate number of calories on their own, but the caloric content of this side dish increases when you add milk and butter during the mashing process. The U.S. Department of Agriculture reports that a cup of homemade mashed potatoes with whole milk contains 174 calories. Adding butter to the potatoes increases the caloric value to 237 calories per cup. The exact number of calories in your gravy depends on its meat source. Per cup, canned beef gravy contains 123 calories, canned chicken gravy has 188 calories and canned turkey gravy has 121 calories.