How to Read Food Labels: A Simple Guide

How do you read food labels? First, compare values per 100 g or 100 ml, then check the serving you’ll actually eat. In the nutrition table, pay attention to kcal, sugars, and salt, and check the order of ingredients in the ingredients list. For example, a 40 g serving of a product containing 440 kcal per 100 g provides about 176 kcal.

Why start by checking the values per 100 g?

Values per 100 g or 100 ml let you compare two products regardless of how the manufacturer defines a serving. This is especially useful for breakfast cereal, yogurt, bread, sauces, and snacks. One package may list a 25 g serving and another a 40 g serving, so the per-serving numbers won’t tell the whole story.

The serving size on a label can be a helpful guide, but it isn’t automatically right for everyone. If you usually eat a bigger bowl of cereal or add fruit and nuts to your yogurt, calculate the values for the amount you actually serve yourself. You can weigh it once or use this method for estimating serving sizes without a scale.

These are rounded example values for a fictional product. The calculation is simple: multiply the value per 100 g by the serving weight, then divide by 100. For sugars in this example: 18 g × 40 ÷ 100 = 7.2 g. You can use the same method for calories, protein, fat, and salt.

kJ vs. kcal—what do these numbers mean?

Energy on food labels is listed in kilojoules (kJ) and kilocalories (kcal). These are two units for the same energy, not two different values to add together. One kilocalorie is about 4.184 kJ, so 100 kcal is roughly 418 kJ.

In everyday conversation, we often just say “calories,” even though labels show kcal. When comparing products, stick to one unit—kcal is usually the easiest. You can also check kJ if that’s the larger or more prominent number on the package, but don’t compare one product’s kJ with another product’s kcal.

Energy alone doesn’t tell you everything about a product. Two products with similar kcal may differ in protein, fiber, sugars, and salt. If you track the energy in your meals, this simple way to count calories can also help—the label is one source of information, along with serving size and extras.

How do you check sugars and salt?

The “carbohydrate” value in the table includes different components, while the “of which sugars” row shows how much sugar is in a given amount of the product. That doesn’t mean all the sugars come from added sugar. They may occur naturally in ingredients such as fruit or milk.

That’s why you should check the ingredients list alongside the table. If sugar, glucose syrup, or another sweetening ingredient appears near the top of the list, the product contains more of it than of ingredients listed later. And “no added sugars” doesn’t automatically mean “sugar-free” or “low-calorie.” The product may contain sugars that occur naturally in its ingredients, and energy also depends on factors such as fat and serving size.

Check the salt, too. The table lists the amount of salt, not just sodium. Sodium is one of the components of salt, and the “salt” value on the label takes the sodium conversion into account. When comparing similar products, choose one that better suits your needs—but don’t assume that “less salt” means the product is salt-free.

If the label shows a percentage of the reference intake, remember that it’s a reference point for an average adult, based on a diet of 2000 kcal. It isn’t an individual goal for everyone. Your needs may be different, and the percentages on the label don’t replace tailoring your diet to your health and daily activity.

What does the order of ingredients tell you?

As a rule, ingredients are listed in descending order by weight as used in production. So the first ingredient is usually present in the largest amount, with each one after it present in a smaller amount. If you see sugar, fat, or flour near the top of the list, that suggests it’s an important part of the recipe.

Still, don’t judge a product by a single word. A longer ingredients list doesn’t always mean a worse product, and a short list doesn’t guarantee that it’s right for you. Check what the ingredient names refer to and how the list compares with the nutrition information table.

Allergens such as milk, soy, or nuts should be highlighted in the ingredients list, for example in bold. If you avoid a particular allergen, check the list every time—the product’s recipe may change. “May contain” is a separate warning about the possible accidental presence of an allergen, not an ingredient deliberately added to the product.

How can you avoid being swayed by claims on the front of the package?

The front of the package is designed to catch your eye, not replace detailed information. Claims such as “fit,” “natural,” or “light” may sound appealing, but they don’t tell you how many calories or sugars the product contains, or how much salt it has. “High-protein” also doesn’t automatically mean a product is low in calories or the best choice in every situation.

When you see nutrition claims, check exactly what they refer to. “No added sugars” describes whether sugars have been added, not necessarily the product’s total sugar content. The word “light” should refer to a specific product feature—check whether it means reduced energy, fat, or another component. Compare the claim with the nutrition information and similar products per 100 g.

A simple test can help: turn the package around and check the nutrition table and ingredients before deciding whether the claim on the front really matters to you. If you’re tracking macros, you can also read an explanation of what macronutrients are and see which numbers are worth tracking in your meals.

How do you read food labels when shopping day to day?

You don’t have to analyze every item in detail. When comparing two similar products, follow these steps:

1. Compare calories and selected nutrients per 100 g or 100 ml.
2. Check your actual serving size and calculate its nutrition information.
3. Check the amount of sugars and salt if those are important to you.
4. Review the first ingredients listed and any highlighted allergens.
5. Treat marketing claims as a prompt to check, not as a verdict.

When you log a product in your food diary, match the serving to the amount you ate. EatSee lets you scan a photo of the product label, and the app estimates calories and macronutrients; you can adjust the result if the serving size or an ingredient doesn’t match. You can also use the app’s barcode scanner to scan the product barcode. For instructions, see the article how to scan a product barcode with your phone.

The main rule is simple: compare similar products for the same amount, focus on the values that matter to you, and account for your actual serving. That way, the label becomes more than fine print—it becomes a practical guide when you shop.

This article is for informational purposes only and does not replace advice from a doctor or dietitian. Written by the EatSee editorial team. Editorial policy.