Calories (カロリー) are the source, and the unit of measurement of energy for living things in Toriko. The amount of calories one might possess varies from person to person, however Bishokuya, and those infused with Gourmet Cells tend to have a much higher calorie intake than normal people. As a result, these people tend to consume, and use more than the average person, thus granting them greater stamina than normal, but at a higher price. This allows them to use powerful high energy attacks that would otherwise be impossible.
A thousand calories is a kilocalorie (キロカロリー), and it is this unit of measurement that the use of power is generally measured in the series. Calorie consumption can be cut down, if one were to learn Food Honor, a mental concept that increases concentration, while reducing unnecessary movements. There also seems to be other methods similar to Food Honor that other creatures are capable of using, with similar effects. If one learns the secret of Food Honor and Food Immersion, they would also be able to increase the intake of energy from an Ingredient, while they are digesting it.