The unit of energy found on food packets is typically kilocalories (kcal), also known as Calories (Cal) with a capital C.

While the official unit of energy in the International System of Units (SI) is the joule (J), kilocalories are still widely used in food labeling and nutrition information.

Here's a breakdown:

* 1 kilocalorie (kcal) = 1 Calorie (Cal) = 4.184 joules (J)

So, when you see "100 Calories" on a food label, it means that the food contains 100 kilocalories or 418.4 joules of energy.