A calorie is the standard unit for measuring energy. What we think of as calories when we say "Jolt Cola has 150 Calories in each can" is in fact referring to kilocalories, a unit representing 1000 calories. Another term for kilocalorie is Calorie (note the capital C). So, while a can of Jolt Cola has 150 Calories, it also has 150,000 calories. Try telling someone you ate 3 million calories worth of food yesterday, and see what happens. :)
The caloric energy in what we eat comes from the Fat, Carbohydrates, and Protein levels in foods. Each gram of Fat provides 9 Calories, and each gram of carbohydrates and protein contribute 4 Calories. So, if you were to drink a bottle of Snapple, which contains about 58 grams of carbohydrates, you would get about 232 Calories.
You may think that the most of the calories you need go towards all the movement you do all day, but that's not true; the majority of the calories you get from food go to maintaining your body. Your body has what is called a Basal Metabolic Rate, which is the amount of calories your body needs just to keep going. In most people, about 60% of the calories you consume are used simply in keeping your body's tissues maintained and body processes like your digestive and cardiovascular systems working.