How to read a nutrition label

Start with the serving size trap

The very first thing to check is the serving size and the number of servings per pack. Every figure below it — calories, fat, sugar, sodium — refers to that single serving, not the whole packet. A bag of crisps might list figures for a 25g serving, but if the bag contains 40g, you're getting more than the label's headline numbers suggest.

This is one of the most common ways people misjudge what they're eating. Before you look at anything else, ask: is this serving size realistic for how much I'll actually eat? If not, do the maths — double the numbers if you'll eat double the serving, and so on.

Calories and macronutrients: the core numbers

Once you know the serving size, the calories (energy) figure tells you how much energy that serving provides. Below that, you'll usually find the macronutrient breakdown: fat, carbohydrates, and protein, sometimes with sub-categories like saturates and sugars.

• Fat is broken into total fat and saturated fat (saturates); most guidance suggests keeping saturated fat lower and prioritising unsaturated sources.
• Carbohydrates include total carbs and sugars; fibre is sometimes listed separately underneath.
• Protein is listed as a single figure per serving.

If you're tracking calories or macros with an app, these are the numbers you'd log — but remember to adjust them to match your actual portion, not just the labelled serving.

%DV, added sugars, and sodium

Many labels include a % Daily Value (%DV) or similar reference intake percentage next to each nutrient. This shows roughly how much of an average adult's daily needs one serving provides. As a rough guide, 5% or less is considered low, and 15-20% or more is considered high — useful for quickly judging whether a food is a significant source of sodium, saturated fat, or fibre.

Pay close attention to sugars. Total sugars include naturally occurring sugars (like those in fruit or dairy) as well as added sugars. Where added sugars are listed separately, that figure is the one worth limiting, since naturally occurring sugars come packaged with other nutrients like fibre or calcium.

Sodium is another figure worth checking, especially in packaged, tinned, or ready-to-eat foods, as it adds up quickly across a day. If you're mindful of your sodium intake for health reasons, comparing the %DV across similar products can help you pick a lower-sodium option.

Ingredient list order and what it tells you

Ingredients are legally required to be listed in descending order by weight, meaning the first ingredient makes up the largest proportion of the product, and so on down the list. If sugar, oil, or a refined grain appears in the first two or three ingredients, that's a strong clue about what the product is mostly made of, regardless of what the front of the pack claims.

Long ingredient lists aren't automatically bad, but they're worth a glance if you're trying to identify specific allergens, added sugars under different names (like glucose syrup, dextrose, or maltose), or types of fat (such as palm oil or partially hydrogenated oils).

Per-100g vs per-serving: how to compare products fairly

Most labels show two columns: one per serving, and one per 100g (or 100ml). Serving sizes vary a lot between brands and products — one cereal's serving might be 30g while a competitor's is 45g — which makes side-by-side comparisons using the serving-size column unreliable.

The per-100g column is the fairest way to compare two similar products, because it standardises the measurement. If you're deciding between two brands of yoghurt or two granola bars, line up their per-100g figures for calories, sugar, and fat to see which is genuinely lower, then use the per-serving figures to work out what a realistic portion means for you.

Marketing claims vs the actual label

Front-of-pack claims such as "natural," "light," "low fat," or "high protein" can be genuinely useful, but they're often designed to catch your eye rather than tell the full story. A product marketed as "low fat" may still be high in added sugar to compensate for flavour, and "natural" has no strict legal definition in most places.

The safest approach is to treat these claims as a prompt to check the label yourself rather than take them at face value. If a claim highlights one nutrient (like "low sugar"), it's worth checking the others too, since improving one figure sometimes means a trade-off elsewhere.

Using an app to log what you eat can help take some of the guesswork out of this process — once you've read the label correctly, tracking the accurate serving size and nutrient values makes it much easier to see how a food fits into your overall day.