Just so you know the details: One calorie is the amount of heat energy required at a pressure of one atmosphere to raise the temperature of one gram of water one degree Celsius. What this means is that the more calories you eat, the more energy you have inside of you. When you don’t use that energy, say by playing sports or cooking a meal on your feet, it is stored in your body as fat. A lot of people don’t realize this; now you know that’s how it works.