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Basics of Comparing Packaged Foods Using Labels

Published February 2026 | Educational Article

Introduction to Food Labelling

Packaged foods sold in the United Kingdom carry various types of information on their packaging. This labelling serves regulatory purposes, provides consumer information, and allows for comparison between different products. Understanding how to read these labels is a practical skill for anyone who shops for packaged foods.

This article provides an educational overview of the main types of information found on food packaging in the UK and explains how this information can be used to compare similar products. The content is presented from a neutral, informational perspective.

Regulatory Framework

Food labelling in the United Kingdom is governed by regulations that require certain information to appear on packaged foods. These requirements ensure consumers have access to basic information about what they are purchasing.

Mandatory information typically includes the product name, ingredients list, nutritional declaration, net quantity, date marking, storage conditions if applicable, name and address of the food business operator, and country of origin for certain products.

Understanding that this labelling is regulatory rather than voluntary helps contextualise why certain information appears on all packaged foods sold through retail channels in the UK.

The Nutrition Label

The nutrition label, also called the nutritional declaration, presents standardised information about the nutritional content of the food. In the UK, this information must be presented in a specific format per 100 grams or 100 millilitres, which allows for direct comparison between products.

The mandatory elements of a UK nutrition label include energy expressed in both kilojoules and kilocalories, fat, saturates (saturated fat), carbohydrate, sugars, protein, and salt. These are the seven mandatory elements that must appear on virtually all packaged foods.

Some products voluntarily include additional nutritional information such as fibre, specific vitamins, or minerals. When these appear, they must also be presented in a standardised format.

Understanding Serving Size Information

Many nutrition labels present information not only per 100g/100ml but also per serving. The serving size is typically determined by the manufacturer and represents an amount that might be consumed on a single eating occasion.

Serving sizes can vary between similar products from different manufacturers. When comparing products, using the per 100g or per 100ml values provides a standardised basis for comparison, regardless of how different manufacturers define their serving sizes.

It is worth noting that serving size information is indicative rather than prescriptive. The amount any individual actually consumes may be larger or smaller than the stated serving size depending on personal factors.

The Ingredients List

The ingredients list shows all ingredients used in the product, listed in descending order by weight. This means the ingredient present in the largest amount appears first, and the ingredient present in the smallest amount appears last.

For some ingredients, the percentage by weight must be stated. This typically applies to ingredients mentioned in the product name or emphasised on the packaging. For example, a strawberry yogurt must declare the percentage of strawberries it contains.

Reading ingredients lists provides context about the composition of packaged foods. Two products with similar names may have quite different ingredients lists, revealing differences in formulation and processing.

Allergen Information

UK food labelling regulations require clear allergen information. The main allergens that must be declared include cereals containing gluten, crustaceans, eggs, fish, peanuts, soybeans, milk, nuts, celery, mustard, sesame, sulphur dioxide and sulphites, lupin, and molluscs.

When any of these allergens are present as ingredients, they must be emphasised in the ingredients list, typically through bold text or other highlighting. Additional voluntary warnings about potential cross-contamination may also appear.

For individuals with allergies or intolerances, this allergen labelling provides essential safety information. For others, it simply offers transparency about what the product contains.

Front-of-Pack Labelling

Many packaged foods in the UK feature additional front-of-pack nutrition labelling, often in the form of colour-coded labels showing amounts of fat, saturated fat, sugars, and salt. This voluntary system uses red, amber, and green colours to indicate relative amounts of these nutrients.

These front-of-pack labels are designed to provide at-a-glance information, though they are voluntary and not all products carry them. The colour coding is based on reference intake values and portion sizes.

When present, these labels can facilitate quick comparisons between similar products on the shelf, though they should be considered alongside the detailed nutrition label for complete information.

Date Marking

Packaged foods carry either a use-by date or a best-before date. Use-by dates appear on foods that are highly perishable and could become unsafe to eat after the stated date. Best-before dates appear on less perishable foods and indicate the date until which the product should retain its optimal quality.

Understanding the difference between these two types of date marking helps contextualise food storage and consumption decisions. Use-by dates relate to safety, while best-before dates relate to quality.

Claims and Statements

Food packaging may carry various claims such as low fat, high fibre, source of protein, or other nutritional claims. In the UK and EU, these claims are regulated and can only be used when the product meets specific defined criteria.

For example, a product claiming to be low fat must contain no more than 3g of fat per 100g for solids or 1.5g per 100ml for liquids. A product claiming to be a source of fibre must contain at least 3g of fibre per 100g.

Understanding that these claims are regulated and defined provides context for interpreting them. They are not marketing statements but must meet legal thresholds to be used.

Comparing Similar Products

When comparing similar products, several approaches can be used. The per 100g nutritional values provide a standardised basis for comparison. The ingredients lists reveal compositional differences. Price per 100g allows cost comparison independent of package size.

Different products may prioritise different nutritional characteristics. One brand of breakfast cereal might be lower in sugar but higher in salt than another. One type of ready meal might be lower in fat but higher in salt than a similar product.

The most relevant comparison factors depend on individual priorities, preferences, and circumstances. The labels provide standardised information that can inform these comparisons, but they do not dictate which product is objectively better as this depends on personal context.

Limitations of Label Information

While food labels provide substantial information, they have limitations. They present nutritional content in a standardised format that may not capture all relevant aspects of the food. They do not reflect freshness beyond the date marking. They do not describe taste, texture, or culinary quality. They present information about the product as packaged, which may differ from the product as consumed after preparation.

Labels also necessarily simplify complex information into a compact format. The full nutritional profile of a food extends beyond the seven mandatory elements on the label. The sourcing, processing, and production methods may not be fully described.

Understanding these limitations helps contextualise what labels can and cannot communicate about packaged foods.

Practical Label Reading Skills

Developing familiarity with label reading involves understanding the standard formats used, knowing where to find different types of information on the package, being able to locate and compare per 100g values, reading ingredients lists from start to finish, and recognising the difference between mandatory information and voluntary claims.

These skills develop with practice. The more frequently someone reads food labels, the more quickly they can locate and interpret the information presented.

Cultural and Dietary Context

The relevance of different label information varies depending on cultural background and dietary patterns. Someone following a plant-based diet will scrutinise ingredients lists for animal-derived ingredients. Someone managing sodium intake for health reasons will focus on salt content. Someone with allergies will prioritise allergen information.

The label provides the same information to everyone, but different individuals will attend to different aspects depending on their personal context and priorities.

Changes and Evolution

Food labelling requirements and practices evolve over time as regulations change and voluntary practices develop. Recent decades have seen increased standardisation, more detailed allergen information, and the introduction of front-of-pack labelling schemes.

Future changes may bring additional information, different formats, or new types of disclosure. Understanding that labelling is not static but evolves with regulatory changes and industry practices provides useful context.

Conclusion

Food labels on packaged products in the United Kingdom provide standardised information that enables comparison between similar products. Understanding how to read nutrition labels, ingredients lists, and other mandatory information represents a practical skill for grocery shopping in contemporary food retail environments.

This article has provided an educational overview of food labelling in the UK context. The information is presented to explain how labels work and what information they contain, rather than to prescribe specific approaches to product selection or food choices.

Individual needs, preferences, and priorities vary widely, and label information should be considered within personal contexts rather than as universal prescriptions.

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