Caloriesare the standard unit used to describe theamount of energy provided by food and drinks, so optionBis correct. In nutrition education, calories represent how much potential energy the body can obtain from what you eat. Your body uses this energy to power essential functions such as breathing, circulation, maintaining body temperature, repairing tissues, and supporting movement and exercise.
Calories primarily come from macronutrients:carbohydrates, fats, and proteins(and also alcohol). Each macronutrient contributes a certain amount of energy per gram, and the total calorie content of a food depends on how much of these macronutrients it contains. When energy intake from calories matches energy needs, body weight tends to stay stable. When intake is consistently higher than needs, excess energy is stored (often as body fat). When intake is consistently lower than needs, the body draws on stored energy, which can lead to weight loss.
The other options are related concepts but don’t mean “energy amount.” Anutrientis a broad term for substances the body needs for health (including carbohydrates, fats, proteins, vitamins, minerals, and water). Not all nutrients provide energy—vitamins and minerals, for example, support body processes but do not supply calories.Vitaminsare micronutrients required in small amounts for functions like immunity, vision, and energy metabolism, but they are not a direct measure of energy.Metabolismrefers to the body’s chemical processes that convert food into energy and building blocks; it describes the process, not the unit of energy.
For fitness and health, focusing on both calorie balance and nutrient quality is important—choosing nutrient-dense foods helps support performance, recovery, and long-term wellness.
