Quick Answer: Check the serving size first, since every other number on the label is based on it. Then look at the ingredients list (ordered by quantity, highest first), total sugars versus added sugars, and fibre content. A product with a short ingredients list and under 5g of added sugar per 100g is generally a solid choice.
Nutrition labels look straightforward until you actually try to compare two products side by side and realise the serving sizes are different, one lists sugar per 100g and the other per portion, and somehow neither number tells you what you actually want to know.
This isn’t really your fault. Food labelling is genuinely inconsistent between brands, sometimes deliberately so, in ways that make quick comparison harder than it should be. This guide walks through what to actually look at, in what order, so a label stops being a wall of numbers and starts being useful information.
Start With the Serving Size, Always
Every number on a nutrition label — calories, fat, sugar, everything — is calculated against the stated serving size, not the whole package. This is the single most overlooked detail on any label, and it’s the reason a ‘low calorie’ snack can still deliver most of a day’s sugar allowance if the actual serving size bears no resemblance to what a person would realistically eat in one sitting.
UK labels are required to show values per 100g or 100ml alongside the per-serving figures, and that per-100g column is genuinely the more useful one for comparing between products, since it removes the serving-size manipulation entirely and puts everything on the same footing.
Reading the Ingredients List Properly
Ingredients are listed by weight, from most to least. Whatever appears first is what the product is mostly made of, which is a genuinely quick way to sense-check a product’s marketing against its actual contents — a ‘fruit’ snack listing sugar or glucose syrup before any actual fruit is worth a second look.
A longer ingredients list isn’t automatically bad, but it’s worth noticing when it’s padded with multiple names for the same category of thing — several different sugars (glucose syrup, dextrose, fructose) listed separately can obscure just how much total sugar is actually in the product, since each individual name might rank lower on the list than a single combined ‘sugar’ entry would.
Unfamiliar ingredient names aren’t automatically concerning either — many are simply the scientific or technical name for something ordinary, like ascorbic acid (vitamin C) or tocopherol (vitamin E). The genuinely useful skill here is recognising patterns rather than fearing every unfamiliar word.
Also Read: Debunking the Most Common Diet Myths
Sugar: Total vs Added
Total sugars include naturally occurring sugar (like the lactose in milk or fructose in fruit) alongside anything added during processing. Added sugars — now increasingly listed separately on many labels — are the number worth focusing on, since naturally occurring sugar in whole foods comes packaged with fibre and nutrients that change how the body processes it.
As a rough guide, under 5g of sugar per 100g is considered low, while over 22.5g per 100g is considered high under UK front-of-pack labelling guidance. This applies to total sugar, so it’s worth checking whether a product’s sugar is mostly natural (as in plain yoghurt) or mostly added (as in flavoured yoghurt) before judging the number in isolation.
Fibre, Protein, and the Numbers People Skip
Fibre gets far less attention than sugar or fat on most labels, despite most people in the UK eating well under the recommended 30g daily target. A product with 3g or more of fibre per 100g is considered a source of fibre; 6g or more qualifies as high fibre, which is genuinely worth checking on bread, cereal, and pasta products where fibre content varies enormously between brands.
Protein content matters more for some shoppers than others depending on goals, but it’s worth checking against the ingredients list rather than trusting a front-of-pack claim alone — a product marketed heavily around ‘high protein’ sometimes achieves that status through a fairly modest actual protein boost relative to a standard version.
Also Read: Anti-Inflammatory Foods to Add to Your Weekly Diet
Front-of-Pack Traffic Lights
The red, amber, green colour coding used on many UK packaged foods gives a fast visual summary of fat, saturated fat, sugar, and salt levels per serving. It’s a genuinely useful quick-glance tool, but it’s worth remembering it’s based on the manufacturer’s stated serving size, which circles back to the earlier point — always double-check that the serving size looks realistic before trusting the colour coding at face value.
A product with all-green traffic lights isn’t automatically the healthiest option in a broader sense — it just means it’s relatively lower in those four specific measures. Whole foods with no packaging at all (fruit, vegetables, plain meat) don’t carry traffic light labels but are still generally the foundation of a balanced diet regardless of colour coding elsewhere on the shelf.
Health Claims vs Nutrition Claims: Knowing the Difference
Nutrition claims (like ‘low fat’ or ‘high fibre’) refer to specific, regulated nutrient thresholds and are relatively reliable indicators once you know the definitions. Health claims (like ‘supports heart health’) are a different regulatory category entirely, and while genuine health claims do require some evidence to display in the UK, the wording is often vague enough to apply to a broad range of products, some more deserving of the claim than others.
A useful habit is treating front-of-pack health claims as a prompt to check the actual nutrition panel, rather than as a conclusion in themselves. A product claiming to ‘support digestive health’ might genuinely contain a meaningful amount of fibre, or it might contain a token amount alongside a lot of added sugar — the claim alone doesn’t tell you which.
Also Read: Meal Prep for Beginners: A No-Stress Weekly System
A Simple Label-Reading Routine for Regular Shopping
Building a genuinely quick habit — checking serving size, then the first three ingredients, then sugar per 100g — takes only a few seconds once it’s practiced, and covers most of what actually matters for everyday comparison shopping without needing to analyse an entire label every time.
This is particularly useful when comparing near-identical products on a shelf, like two brands of granola or two ready meals, where the front-of-pack marketing looks almost identical but the actual nutritional content, once you check, can differ meaningfully between them.
Quick Reference: Low vs High (per 100g)
| Nutrient | Low | High |
|---|---|---|
| Sugar | 5g or less | 22.5g or more |
| Saturated fat | 1.5g or less | 5g or more |
| Salt | 0.3g or less | 1.5g or more |
| Fibre | Under 3g (low) | 6g or more (high) |
Key Takeaways
- Always check the serving size first — every other figure on the label is calculated against it.
- The per-100g column is more useful than per-serving figures when comparing between products.
- Ingredients are listed by weight, highest first, making the first few entries the most revealing.
- Added sugar matters more than total sugar, since naturally occurring sugar in whole foods behaves differently in the body.
- Fibre is commonly overlooked but worth checking specifically on bread, cereal, and pasta products.
Conclusion
Reading a nutrition label properly isn’t about memorising every number — it’s about knowing which two or three actually matter for your own goals and checking those consistently. Serving size, ingredients order, and added sugar cover most of what’s genuinely useful for everyday shopping decisions. Everything else on the label is supporting detail, worth a glance but rarely the deciding factor.
Frequently Asked Questions
Why do some products list sugar per serving and others per 100g?
UK regulations require the per-100g figure, but manufacturers can additionally display per-serving figures, which is why labels sometimes look inconsistent between brands, and comparing the per-100g column directly avoids this issue.
Is a product with no added sugar always a healthier choice?
Not necessarily — a ‘no added sugar’ product can still contain naturally high sugar levels from fruit concentrate or similar ingredients, so it’s worth checking the total sugar figure regardless of that specific claim.
What does it mean if an ingredient is listed as a percentage on the label?
UK regulations require certain highlighted ingredients, especially those named in the product title, to show their percentage of the total product, which helps confirm how much of a named ingredient is genuinely present.
Are ‘natural’ or ‘organic’ claims regulated the same way as nutrient values?
No, terms like ‘natural’ aren’t strictly defined in the same regulated way that nutrient values are, so these claims are worth treating as marketing language rather than a guarantee of nutritional quality.
How reliable are the traffic light colours on UK food packaging?
They’re a genuinely useful quick reference for fat, saturated fat, sugar, and salt, calculated using standardised government thresholds, though they don’t account for overall nutritional value or serving realism, so pairing them with a quick label check is still worthwhile.
Why do some similar products have very different sugar content?
Recipe formulation varies significantly between brands, particularly for products like yoghurt, cereal, and sauces, where added sugar can range widely even between products that look nutritionally similar at a glance, which is exactly why checking the actual figure matters more than assuming based on category.
Is it worth checking labels on fresh produce like fruit and vegetables?
Whole fresh produce doesn’t typically carry a nutrition label since it’s a single, unprocessed ingredient, so label-reading is mainly relevant for packaged and processed foods rather than the fresh food aisle.
