We need energy for all of our body's activities — everything from breathing and thinking to running or skiing. From a heartbeat to the blink of an eye, each of the body's activities requires the body to convert the energy in food into energy the body can use. Therefore, calories cannot be categorized as being either good or bad, but as essential for our survival.
The challenge for most of us is to balance the calories we consume with the calories we actually need for our body's activities. To gain weight, we eat more calories than we use. To lose weight we can eat fewer calories, burn more calories through activities, or (preferably) do a combination of the two. Extra calories above what our body needs are stored in the body as fat.
So make conscious decisions when choosing foods and the quality of calories they contain. Foods low in fat and high in water, such as fruits, vegetables and whole grains, are generally lower in calories. Foods higher in fat and concentrated carbohydrate sweeteners, such as snack foods and baked goods, contain more calories. Find a healthy balance between low and high calorie foods to give the body the energy it needs without tipping the scale.