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Nutrition Crash Course

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Lesson 7 of 7 8–11 min read

Understanding Food Labels

This final lesson brings the course together. You'll learn how to read a nutrition label, what ingredient lists and allergen information tell you, and why labels look different depending on the country.

Read the original sources

How to read a nutrition label in 5 steps

New to labels? Use these five steps on any pack. The example below is laid out like a UK-style table; US Nutrition Facts labels show the same ideas in a different format.

Example only – fictional breakfast cereal

Nutrition. Pack contains about 12 servings of 30g.
Typical valuesPer 100gPer 30g serving
Energy1610 kJ / 385 kcal483 kJ / 116 kcal
Fat8.0g2.4g
of which saturates1.5g0.5g
Carbohydrate64g19g
of which sugars12g3.6g
Fibre9.0g2.7g
Protein10g3.0g
Salt0.6g0.18g

Ingredients: Whole grain wheat (70%), oats, sugar, raisins, sunflower oil, salt. Allergens: see ingredients in bold.

This label is made up for teaching. It is not a real product and its figures are not nutrition data.
  1. Check the serving size and servings per pack. Here a serving is 30g and the pack holds about 12. If you pour 60g, double the per-serving figures. US labels put serving size at the top.
  2. Check the energy. UK and EU labels give energy in kJ and kcal (what people usually call "calories"). US labels show "Calories" per serving.
  3. Compare the key nutrients. Look at protein, sugars, saturated fat ("saturates" in the UK) and salt. UK/EU labels list salt; US labels list sodium instead (salt ≈ sodium × 2.5).
  4. Use per-100g to compare products fairly. UK/EU tables always show per 100g (or 100ml), so two cereals with different serving sizes can be compared directly. US labels usually show per serving only, so check that serving sizes match before comparing.
  5. Check the ingredients and allergens. Ingredients are listed by weight, largest first. In the UK and EU, the 14 major allergens are emphasised in the ingredients list (for example in bold); US labels use a "Contains" statement or the ingredients list.

Some labels also show a %RI (UK/EU Reference Intake) or %DV (US Daily Value). These are general reference amounts based on a typical adult, not personal targets, so use them only as a rough guide to whether a food is higher or lower in a nutrient.

Labels differ by country

There is no single worldwide food label. This lesson compares UK/EU conventions with US conventions because they are widely seen, but other countries have their own rules. Always check what applies where you live.

Per 100g, per 100ml and per serving

  • UK and EU nutrition tables are shown per 100g (or per 100ml for drinks), and may also show values per portion.
  • US Nutrition Facts labels are based on a stated serving size, shown at the top of the label.

Per-100g values are useful for comparing products fairly. Per-serving values tell you about the amount the manufacturer has chosen, which may not match what you eat.

The nutrients listed

How common label lines differ. Simplified; see the official sources for full rules.
TopicUK / EUUS
EnergykJ and kcalCalories
FatFat, of which saturatesTotal Fat, Saturated Fat, Trans Fat
CarbohydrateCarbohydrate, of which sugars; fibre, if shown, listed separatelyTotal Carbohydrate, including Dietary Fiber, Total Sugars and Added Sugars
ProteinProteinProtein
Salt / sodiumSaltSodium

Salt and sodium are not the same number: salt is sodium chloride, so a salt figure is larger than the sodium it contains. Make sure you're comparing like with like. For the energy, protein, carbohydrate and fat lines, see Lessons 2, 3, 4 and 5.

Ingredient lists and allergens

Ingredients are listed in descending order by weight, so the first ingredients make up the largest share of the product. This is the case in the UK, EU and US.

Allergens (rules vary by country)

In the UK and EU, pre-packed foods must list ingredients with specified allergens emphasised, for example highlighted in bold. In the US, major food allergens must be declared on the label, either in the ingredient list or in a “Contains” statement. The list of allergens covered differs between countries.

If you or someone you cook for has a food allergy, follow the advice of your healthcare professional and your national food safety authority.

Front-of-pack labels

Many products also carry a simplified label on the front of the pack. These schemes vary:

  • UK: a voluntary front-of-pack scheme shows energy, fat, saturates, sugars and salt, often with reference intakes. Many labels use red, amber and green colour coding to show at a glance whether fat, saturates, sugars and salt are high, medium or low.
  • Some other European countries use different schemes, such as Nutri-Score.
  • US: front-of-pack information is set by manufacturers and FDA rules, and differs from UK and European schemes.

Front-of-pack labels are a quick guide, but the full nutrition table and ingredient list give more detail.

Comparing two products

Hypothetical comparison

Two fictional yoghurts: Yoghurt A has 12g sugars per 100g in a 150g pot. Yoghurt B has 8g sugars per 100g in a 200g pot.

  • Per 100g, A has more sugars than B (12g vs 8g).
  • Per pot: A = 12 ÷ 100 × 150 = 18g; B = 8 ÷ 100 × 200 = 16g.

These products are invented for learning. Comparing per 100g shows which is lower in sugars; comparing per pot shows what you actually eat.

Try it yourself (hypothetical food)

A fictional drink label shows 5g sugars per 100ml. How many grams of sugars are in a 330ml can?

Use (sugars per 100ml ÷ 100) × millilitres.

Common label traps

  • Different serving sizes: two products can list different portions, so per-serving figures can't be compared directly. Use per-100g values where available.
  • Packs with several servings: a pack may contain more than one serving; the figures may apply to only part of it.
  • Salt vs sodium: they're different numbers for the same component.
  • Reference percentages: %RI (UK/EU) and %DV (US) use different reference amounts and are not personal targets.
  • Claims on the front: words like “light” or “high protein” are regulated differently in different countries. Check the nutrition table.

Practise with real foods

Use the calculator to see nutrient values from USDA FoodData Central and compare portions.

Check your understanding

4 questions. Choose an answer for each, then check.

  1. 1. Why are per-100g values useful?
  2. 2. How are ingredients ordered in an ingredient list?
  3. 3. Are salt and sodium figures the same number?
  4. 4. Is the UK colour-coded front-of-pack label used in every country?

Answer all 4 questions to check your work.

Lesson summary

  • Label rules differ by country; UK/EU and US are compared here, but neither is universal.
  • UK/EU tables are per 100g/100ml; US labels are per serving.
  • Check whether a label shows salt or sodium, and how carbohydrate and fibre are counted.
  • Ingredients are listed by weight; allergen rules vary by country.
  • Front-of-pack schemes are quick guides; the full table gives more detail.
  • Watch for serving-size differences when comparing products.

Further reading & sources