A calorie is the amount of heat energy needed to increase the temperature of 1 gram of water by 1 degree Celsius. 1000 calories = a Calorie (same word, just capitalized) also called a kiloCalorie. Generally when referring to Calorie content, we’re talking about the capital “C” Calorie. Instead of Calories, most of the world uses kilojoules. 4.184 kilojoules = 1 Calorie. Foods that are high in calories but low in nutritional value are said to contain “empty” calories. These are usually foods with added sugar and/or solid fats (fats that are solid at room temperature). There are also “negative” calories. This refers to foods that contain fewer calories than digesting requires, thus netting negative calories. In reality, digestion is figured into a food’s calorie count. Regardless, a food thought to have “negative” calories is still extremely low in calories. Want to know how many calories are in your favorite food or beverage? Text 542542 (costs $1.49 plus any standard messaging charges from your carrier).