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What is a calorie?

Medicine & HealthLesson on requestFree to read

Quick answer

A calorie is a unit of energy — specifically the energy in food and the energy your body burns. Eat more calories than you burn and you gain weight; burn more than you eat and you lose it. It measures the energy food provides and the body uses.

Key things to understand

  1. It measures the energy food provides and the body uses.
  2. The 'calories' on food labels are actually kilocalories (kcal).
  3. Energy balance (in vs out) drives weight gain or loss.
  4. Different foods provide different calories per gram (fat is densest).

People also ask

What is a calorie in food?
A measure of how much energy that food gives your body when digested.
How many calories should I eat a day?
It varies by age, size, and activity, but a common rough guide is about 2,000–2,500 for adults.
Are all calories the same?
Energy-wise yes, but foods differ in nutrition and how full they keep you, so quality matters too.

Part of the guide: Food & Kitchen Science →