How to read a food label: everything the pack is telling you
A food label has four parts to read: the ingredient list (ordered by weight, allergens emphasised), the nutrition panel (compare per 100 g, not per portion), additives and E-numbers, and origin and claims. Ingredients tell you what it is; nutrition tells you how much; the front of pack is marketing.
The ingredient list is the most honest part of the pack
Everything on the front is marketing. The ingredient list is regulated, and it follows two rules that give you a lot of information for free.
Rule one: descending order by weight. The first three ingredients are most of the product. If sugar, or any of its aliases, appears in the first three, that is a sugary product regardless of what the front says.
Rule two: allergens must be emphasised. In the EU and UK, the 14 declarable allergens must stand out from the surrounding text, usually in bold. If you scan an ingredient list and see nothing emphasised, either there are no declarable allergens or something is wrong with the label.
A manufacturer can move sugar down the list by splitting it. Instead of "sugar" at position two, you get glucose syrup at five, fructose at seven, dextrose at nine and invert sugar syrup at eleven. Individually each is small. Together they are the second ingredient. Count them as one when you read.
Aliases to recognise: glucose syrup, fructose, dextrose, maltodextrin, invert sugar syrup, molasses, treacle, agave nectar, fruit juice concentrate, honey, rice syrup, barley malt extract.
The nutrition panel
In the EU, per-100 g figures are mandatory, and they are the only figures that compare honestly across products. Per-portion figures are optional, and the portion size is chosen by the manufacturer.
Rough thresholds per 100 g, drawn from UK front-of-pack traffic-light guidance:
| Nutrient | Low (green) | High (red) |
|---|---|---|
| Fat | ≤ 3 g | > 17.5 g |
| Saturated fat | ≤ 1.5 g | > 5 g |
| Sugars | ≤ 5 g | > 22.5 g |
| Salt | ≤ 0.3 g | > 1.5 g |
These are guides rather than rules. Olive oil is red for fat and is not a bad food. Use them for comparison within a category, which is what they were designed for.
Additives and E-numbers
Additives appear in the ingredient list either by name or by E-number, sometimes both. The number range tells you the function: 100s are colours, 200s preservatives, 300s antioxidants, 400s thickeners and emulsifiers, 600s flavour enhancers, 900s glazes and sweeteners.
An E-number is not a warning; E300 is vitamin C. But a few are worth learning: E120 carmine is crushed insects, E904 shellac is lac-bug resin, E441 is gelatin, and E471 may be plant or animal fat with no way to tell from the label.
Origin, claims and traps
Country of origin is mandatory for some categories, including fresh meat, honey, olive oil and most fruit and vegetables. It is voluntary for many processed foods. "Packed in" and "produced in" are not the same as "origin of ingredients".
Regulated claims have legal definitions. "Low fat" means ≤ 3 g per 100 g. "Sugar-free" means ≤ 0.5 g per 100 g. "Source of fibre" means ≥ 3 g per 100 g. These are enforceable.
Unregulated words mean nothing in law: natural, wholesome, artisan, farmhouse, goodness, inspired by, clean. A "farmhouse" loaf has never been near a farm.
It means no sugar was added during manufacture. A fruit juice with no added sugar can still carry 10 g of sugar per 100 ml from the fruit itself. The claim is true and the drink is still sugary.
Where scanning fits
Everything above is readable by eye if you have five minutes and good light. In a supermarket you have neither.
Scanning does the mechanical part: parsing the list, matching additives against their aliases, highlighting allergens, converting the nutrition panel into a comparison, so that your attention goes to the judgement, which is the part software cannot do.
Learn to read a label properly anyway. Then let something else do it forty times per shop.
How to check this in FoodCheckr- Scan the barcode to get the whole label parsed at once.
- Read the ingredient list. Allergens appear highlighted inline.
- Check the nutrition tiles for calories, sugar, fat and protein.
- Scan a competing product and use Compare for a per-metric verdict.
- Use Analyze with AI when an ingredient list is long and you want it explained.
Frequently asked
What order are ingredients listed in?
Descending order by weight at the time of manufacture. The first three ingredients make up most of the product. Watch for split sugars. Glucose syrup, fructose, dextrose and invert sugar listed separately can together outweigh an ingredient sitting above them.
How to spot ultra-processed foodShould I read per 100 g or per portion?
Per 100 g, always, when comparing products. Per-100 g figures are mandatory in the EU and standardised. Portion sizes are chosen by the manufacturer and are frequently smaller than anyone eats.
Compare two products properlyDoes "natural" mean anything on a label?
Almost nothing in law. "Natural flavouring" has a technical definition, but "natural", "wholesome", "artisan" and "farmhouse" are unregulated marketing words. Regulated claims like "low fat", "sugar-free" and "source of fibre" do have enforceable legal thresholds.
Read the additive guideHow do I know if an additive is animal-derived?
Usually you cannot from the label alone, which is the core frustration. E120, E441, E901 and E904 are known animal or insect derived. E471 and E920 could be either and are not required to say. A scanner flags which ingredients need checking so you know what to ask the manufacturer.
See the hidden animal ingredients guide