Calories: reading the energy label

Start with the essentials

Calories measure the energy in food and drinks. Labels often show kcal (kilocalories). Energy needs vary with age, size and activity.

Worked example: if a label says 200 kcal per 100 g and you eat 50 g, that portion provides 100 kcal. This is an example calculation, not a specific food value.

Per serving is not always per pack

Read the serving description before using the number. A package can hold more than one serving, and the amount you eat can be smaller or larger than the label’s example.

Worked example: a fictional snack contains 120 kcal per 30 g serving. Two servings, or 60 g, would provide 240 kcal. Half a serving would provide 60 kcal. These numbers illustrate the calculation, not a real product.

Make an estimate easy to revisit

Record the food name, the portion, and where the number came from: a package label, a menu, or an estimate. This is more informative than a calorie total with no context.

If you do not know the portion, keep a description or photo instead of inventing precision. ‘One small bowl, portion unknown’ is an honest record you can understand later.

Source

NHS · Understanding calories

The essentials summarise the source above. Diary examples are written by Nobino and are not personalised recommendations from the source organisation.