How do I read a food label?
What the numbers and the ingredients list on packaging actually tell you, and the presentational tricks worth knowing about.
- Difficulty
- beginner
- Time
- 20 min
- Read
- 2 min
Short answer
Read the per-100g column rather than per-portion, because portion sizes are chosen by the manufacturer. Ingredients are listed by weight, heaviest first, so the first three tell you most about what a product actually is. Front-of-pack claims are marketing; the back of the pack is the regulated part.
Food labelling is regulated on the back and largely unregulated in tone on the front. Knowing which parts carry legal meaning — the ingredients list, the nutrition table, the allergen highlighting — and which are marketing lets you assess a product in about ten seconds.
Step by step
- Use the per-100g column for comparisons between products.Per-portion figures use manufacturer-chosen portion sizes, which are often smaller than anyone actually eats.
- Read the first three ingredients.Ingredients are listed in descending order by weight, so those three are most of what you're buying.
- Look for the many names sugar appears under.Syrup, molasses, concentrate, dextrose, maltose, honey and others all count. Splitting sugar across several names moves each further down the list.
- Check the allergen information, which is legally highlighted.In the UK and EU, the fourteen major allergens must be emphasised in the ingredients list, usually in bold.
- Distinguish 'use by' from 'best before'.'Use by' is a safety date. 'Best before' is about quality and food is often fine after it.
- Treat front-of-pack claims with scepticism.Some terms are legally defined ('low fat', 'source of fibre'); others like 'natural' and 'artisan' carry little regulatory weight.
- Check what the product actually is if it names something specific.Percentage labelling rules mean a product highlighting an ingredient must state how much it contains. Often less than expected.
- Compare traffic-light colours between similar products rather than in isolation.They're most useful for comparison, not as a verdict on any single item.
Tips
- 'Reduced fat' means reduced relative to the standard version of that product, not that it's low in fat. A reduced-fat crisp is still a crisp.
- Products low in one thing are frequently higher in another — reduced-fat products often contain more sugar to compensate for texture and flavour.
- Serving sizes on the front are often deliberately small. Always cross-check against the per-100g column.
- The ingredients list is the most informative part of any package and the least designed to appeal.
Common mistakes
- Comparing per-portion figures between brands — Portion sizes differ between manufacturers, so the numbers aren't comparable. Use per-100g.
- Trusting front-of-pack claims — Some are legally defined, many aren't. The regulated information is on the back.
- Ignoring the ingredients order — Descending weight order tells you what the product mostly is, which the nutrition table doesn't.
- Treating 'best before' as a safety date — It's a quality indicator. 'Use by' is the safety one.
Questions people ask
What's the difference between use by and best before?
'Use by' is a safety date on perishable food and shouldn't be exceeded. 'Best before' relates to quality — food is often perfectly good afterwards, judged by appearance and smell.
Are traffic light labels reliable?
They're a reasonable quick comparison between similar products, based on defined thresholds per 100g. They don't capture everything about a food, so they're best used comparatively.