Medicine & Health
What is A calorie?
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.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains a calorie.
Key things to understand
- 1It measures the energy food provides and the body uses.
- 2The 'calories' on food labels are actually kilocalories (kcal).
- 3Energy balance (in vs out) drives weight gain or loss.
- 4Different foods provide different calories per gram (fat is densest).
Frequently asked questions
- 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.