Food energy

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Food energy is the amount of energy obtained from food that is available through cellular respiration. It is measured in calories or joules. The energy is used by the body to perform various functions, including maintaining body temperature, growth, and physical activity.

Measurement

Food energy is typically measured in kilocalories (kcal) or kilojoules (kJ). One kilocalorie is equivalent to 4.184 kilojoules. The energy content of food is determined by its composition of macronutrients: carbohydrates, proteins, and fats.

Macronutrients and Energy

• Carbohydrates: Provide approximately 4 kcal (17 kJ) per gram.
• Proteins: Provide approximately 4 kcal (17 kJ) per gram.
• Fats: Provide approximately 9 kcal (37 kJ) per gram.

Energy Requirements

The amount of food energy required by an individual varies based on factors such as age, sex, weight, height, and level of physical activity. The Basal Metabolic Rate (BMR) is the amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state.

Dietary Guidelines

Different countries have established dietary guidelines to help individuals meet their energy needs. These guidelines often include recommendations for daily caloric intake and the proportion of calories that should come from carbohydrates, proteins, and fats.

Energy Balance

Energy balance is achieved when the amount of food energy consumed matches the amount of energy expended. Positive energy balance, where intake exceeds expenditure, can lead to weight gain, while negative energy balance, where expenditure exceeds intake, can lead to weight loss.

Related Concepts

• Metabolism
• Thermic effect of food
• Physical activity level
• Dietary Reference Intake
• Nutrition

See Also

• Calorimetry
• Energy density
• Nutritional value
• Basal Metabolic Rate
• Thermic effect of food