Calorie

Definition

A calorie is the unit of energy provided by food. In nutrition, the kilocalorie (kcal) is used, equivalent to 1000 physical calories.

How it works

1g of carbohydrates provides 4 kcal, 1g of protein 4 kcal, 1g of fat 9 kcal, and 1g of alcohol 7 kcal. Average needs are 2000 kcal/day for women and 2500 for moderately active adult men.

Role

Quantify the energy content of food to balance energy intake.

Examples

• An apple: ~80 kcal
• Plain yogurt: ~60 kcal
• 100g cooked pasta: ~150 kcal

Recommendations

Average needs: 2000 kcal/day for women, 2500 for men.

Key takeaway

Counting calories is useful but insufficient — nutritional quality matters as much as quantity.

Related terms