Food labels: how to compare them without fixating on one number

What the label has to say

The EU's common rules are set out in Regulation (EU) No 1169/2011. The mandatory particulars include the name of the food, the list of ingredients, ingredients that cause allergies or intolerances, the quantity of certain ingredients, the net quantity, the best-before or use-by date and the nutrition information.¹ The latter has been mandatory since December 13, 2016.¹

The mandatory nutrition information has seven items in a fixed order: energy value (in kJ and kcal), fat, of which saturates, carbohydrate, of which sugars, protein and salt. It can be supplemented with others, such as dietary fiber, monounsaturated and polyunsaturated fat or certain vitamins and minerals, which slot into their place within that same order. Everything must appear together, in the same field of vision and, if there's room, in table form.¹

• Sugars are all the monosaccharides and disaccharides in the food:¹ the figure adds up those it contains naturally, such as the sugars in milk or fruit, and the added ones, without separating them. To find out whether there are added sugars, you have to look at the ingredients.
• Salt isn't just added salt: it's the food's total sodium multiplied by 2.5.¹ The label may state that it comes only from naturally occurring sodium.¹
• Fiber isn't one of the seven mandatory items: it appears if the manufacturer decides to declare it,¹ and it's mandatory when the package makes a claim about it, such as “source of fibre.”²

Some foods don't have to carry nutrition information: among others, unprocessed products made of a single ingredient, such as fresh fruit and vegetables, water, herbs and spices, coffee and tea with no other ingredients, and packages whose largest surface measures less than 25 cm².¹ The fact that an apple or a fresh fish fillet comes without a table says nothing about its composition; it says the rules don't require one.

Per 100 g or per portion: which to use for comparing

The table always gives values per 100 g or per 100 ml. The manufacturer can also add a column per portion or per unit, provided it states how many grams that portion weighs and how many portions the package contains.¹ On the front of the package it can repeat the energy value, alone or together with fat, saturates, sugars and salt. If it repeats all five, the nutrients may be given per portion only, but energy must appear per 100 g or 100 ml and also per portion.¹

Sometimes the label gives percentages: “X% of the reference intake.” It's a figure calculated from values that the regulation sets for an average adult—for example, 2,000 kcal, 90 g of sugars or 6 g of salt a day—and the label must say so with the statement “Reference intake of an average adult (8 400 kJ/2 000 kcal).”¹ They're references that make labels comparable, not what a particular person needs.

AESAN explains that the Nutri-Score is calculated per 100 g and not per portion because a per-portion calculation doesn't allow products to be compared and could lead people to underestimate what they actually eat.³ The same logic applies to reading the table: two portions of different sizes can't be compared with each other; 100 g of one and 100 g of the other can.

The ingredients list: order, percentages and allergens

The list includes all the ingredients in descending order of weight, as they are added when the food is made.¹ The first one is the one that weighs the most in the recipe; one that appears at the end is present in a small amount. There are technical exceptions: added water, for example, is ranked by its weight in the finished product, and ingredients that make up less than 2% can go at the end in any order.¹ The order doesn't give amounts, but it does let you see, for example, whether sugar comes before or after the cereal, or whether a product contains several forms of sugar spread throughout the list.

When an ingredient appears in the product's name, is emphasized on the package in words or pictures, or is essential to characterize the product, its quantity must be stated,¹ as a percentage, next to the name or in the list of ingredients.¹ That's what lets you compare two products with the same name, such as two strawberry yogurts: the percentage tells you how much fruit each one contains. If the food loses moisture during production, for example when it's baked, the percentage is calculated on the finished product, and when that would exceed 100%, the label states how many grams of the ingredient were used to make 100 g of product.¹

The regulation lists 14 groups of substances that cause allergies or intolerances, among them cereals containing gluten, eggs, milk, tree nuts, peanuts, soybeans, fish and sesame. When they're in the product, they must appear in the list of ingredients emphasized with a different font, style or background color; if there's no list, with the word “contains.”¹ If you have an allergy or an intolerance, or someone in your household does, the health professional who looks after you is the one who tells you what to avoid and how; this article only describes how it's labeled.

What the Nutri-Score sums up, and what it leaves out

The Nutri-Score is a scale of five letters and colors, from A in dark green to E in dark orange, that grades a food's overall nutritional quality.³ It's calculated from the product's values per 100 g or 100 ml: it gives points against for energy, saturated fat, sugars and salt, and points in favor for fiber, protein and the proportion of fruit, vegetables and legumes; the balance is translated into a letter.³⁴ It's derived from the nutrient profiling system of the UK Food Standards Agency,³ and it has its own rules for some groups, such as fats, oils, nuts and seeds.⁴

The letters aren't a fixed property of the food: they depend on the algorithm. The scientific committee shared by Spain, Germany, Belgium, France, Luxembourg, the Netherlands and Switzerland revised it in 2022 for foods and in 2023 for beverages, and AESAN states that the new calculation has applied since January 1, 2024, with a two-year transition period for products already on the market.³ Going by those dates, that period ran until the end of 2025. In that revision, for example, most olive, rapeseed and walnut oils moved from C to B in the product databases from Belgium, France, Germany and the Netherlands that the committee worked with.⁴ It follows that, during the transition, letters calculated with the old algorithm and with the new one could coexist in stores.

According to AESAN, the Nutri-Score is for comparing products in the same category, such as two breakfast cereals or two sauces; the same type of product from different brands; or products from different groups that substitute for each other at the same time of day, such as a yogurt and another dairy dessert. AESAN also makes clear what it doesn't do: it isn't intended to recommend eating particular foods, which is the job of dietary guidelines, and it doesn't take into account the degree of processing, the environmental impact or the origin of the product.³

Nor does it assess a diet. AESAN itself points out that a varied diet is based above all on fresh plant foods, such as vegetables, fruit and legumes, with the Mediterranean diet as the model,³ and many of those foods, when they're unprocessed and made of a single ingredient, don't have to carry a nutrition table.¹ We explain what characterizes that pattern, beyond any single food, in the article on the Mediterranean pattern.

“Source of fibre,” “light,” “with no added sugars”: what they mean

The phrases and symbols on the front of the package that attribute a nutritional quality to a food are called nutrition claims, and those that link it to health are called health claims. They're regulated by Regulation (EC) No 1924/2006: they can't be false, ambiguous or misleading, or encourage people to eat too much of a food.² Only the nutrition claims listed in the regulation's annex are allowed, and only under the conditions it sets.²

Health claims, such as those describing the role of a nutrient in the body, are prohibited unless they're authorized and included in the EU lists.² At least in 2020, there was an important exception: in 2012 the Commission put 2,078 claims about plants and their preparations “on hold,” and, according to its 2020 evaluation, they could still be used under each company's responsibility until a decision was taken on them. In that evaluation, the Commission warned that consumers may believe these effects have been scientifically assessed, when they haven't.⁶ Authorized claims must be accompanied by a statement on the importance of a varied and balanced diet and a healthy lifestyle, and by the quantity of the food and the way of eating it needed to obtain the effect. A generic benefit phrase, such as “good for your wellbeing,” can only be used together with a specific authorized claim, and claims about the rate or amount of weight loss aren't allowed.²

A nutrition claim is about a nutrient, a substance or energy, not about the whole product; a health claim is about the relationship between a food or one of its components and health.² The regulation provided for the Commission to set, by January 19, 2009, nutrient profiles: composition conditions, above all for fat, sugars and salt, that a food would have to meet in order to carry claims.² In its 2020 evaluation, the Commission found that these profiles had not been set and that, without them, consumers were still coming across claims on foods high in fat, sugar or salt.⁶ So, at least in 2020, nothing prevented a cereal high in sugars from being advertised as a “source of fibre”; and, with or without profiles, that phrase doesn't tell you whether it has more or fewer sugars than another cereal.

Reduction of disease risk claims refer to a risk factor, not to the disease, and must add that the disease has multiple risk factors and that altering one of them may or may not have a beneficial effect.² If that idea reaches you in a headline with figures, it helps to know how to read relative and absolute risk.

How to compare two products in a minute

A practical reading order follows from all of the above; it isn't a rule or a method that has been studied.

1. Compare like with like. Two products in the same category or that you'll use for the same thing, such as two loaves of sliced bread or two tomato sauces. That's also the use AESAN gives the Nutri-Score.³
2. Go to the per 100 g or 100 ml column. Look at the same items on both packages, not just one: energy, saturated fat, sugars, salt and, if it's declared, fiber.
3. Read the beginning of the ingredients list and the percentage of the ingredient that gives the product its name.
4. If both carry the Nutri-Score, use it as a summary of the comparison, not as a substitute for the previous steps.
5. Take front-of-pack claims for what they are: a threshold met for one nutrient.
6. Go back to the portion at the end, but to yours: if you usually serve yourself twice the portion on the package, double its figures.

Doing this every time in the aisle is tiring. An alternative is to compare the products you buy often just once, without hurrying, and write the one you choose on your shopping list—a way of setting up your environment so the decision is already made.

A label describes a product; it doesn't say what place it should have in your diet. If you have an illness, take medication that changes what you can eat or follow eating guidelines given to you by a health professional, it's those guidelines, not the label, that determine which figures to look at.