Energy in food is measured by which unit?

The correct unit for measuring energy in food is calories. Calories represent the amount of energy that food provides when consumed. In nutritional contexts, the term "calorie" is often used to refer to a kilocalorie (the amount of energy needed to raise the temperature of one kilogram of water by one degree Celsius), which is commonly what consumers see on food labels. Understanding this measurement is vital for assessing dietary intake and energy balance, which can influence weight management and overall health.

Other units listed, like kilojoules, are also valid measures of energy; however, in practice, calories are the most commonly used and recognized unit for food energy in many regions, including the United States. Liters is a unit of volume, and grams measure weight or mass, neither of which directly relate to the energy content of food. Thus, calories are the standard for evaluating and understanding how much energy food provides to our bodies.