A calorie is a unit of energy. If you eat more calories than you need, your body will store the energy for later in the form of fat. If you expend more calories than you intake, you will lose weight, whether you are counting calories to lose weight or to gain it, it helps you to know which foods pack the biggest calorie punch.
Also it is known that fried foods are one of the most calories-rich. Fried chicken, pork rinds and french fries are examples of foods full with calories. While, the chicken tops the list, with 463 calories per 100 g.