Calories and energy from food

Direct answer: A calorie is a unit of energy. Food labels show energy in kcal. FSSAI's labelling rules calculate it from the nutrients: 4 kcal per gram of carbohydrate, 4 per gram of protein, 9 per gram of fat and 2 per gram of dietary fibre. That is why the energy line follows the nutrients.

What is a kcal?

A kilocalorie (kcal) is the unit Indian labels use for energy. When people say 'calories' about food, they usually mean kcal.

How is the energy on a label worked out?

FSSAI's 2020 labelling rules list conversion factors: carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, dietary fibre 2 kcal/g, alcohol 7 kcal/g, organic acids 3 kcal/g, polyols (except erythritol) 2 kcal/g, erythritol 0 kcal/g.

Why does fat carry more energy per gram?

ICMR-NIN describes fats as a concentrated source of energy, giving 9 kcal/g against 4 kcal/g for carbohydrates and proteins.

How much energy do I need?

It varies with age, sex, body size and activity. Module 5 covers energy balance. Labels use 2000 kcal as a reference for an average adult when showing % of daily values.

FAQ

Are all calories the same?

A kcal is the same unit of energy, but foods differ in the nutrients that come with it.

Why do labels mention 2000 kcal?

FSSAI uses 2000 kcal for an average adult as the base for per-serve % contribution.

Further reading

• Serving size on food labels

Sources

• FSSAI, Food Safety and Standards (Labelling and Display) Regulations, 2020 (compendium Version-I, 23.09.2021), fssai.gov.in, regulation 5(3)(b) and 5(3)(e)(i); compendium PDF pp. 9–10 (definitions, 2000 kcal reference) and p. 13 (energy factors)
• ICMR-NIN Expert Committee, Dietary Guidelines for Indians-2024 (DGI 2024), nin.res.in/dietaryguidelines/pdfjs/locale/DGI_2024.pdf, Guideline 1 (Carbohydrates, Proteins, Fats: PDF pp. 25–26 / printed pp. 8–9)