How to Compare Two Foods Using the Nutrition Label

Published 15 October 2026 · Updated 18 October 2026 · Sláinte Editorial

You are standing in Tesco with two jars of pasta sauce.

One is Tesco's own-brand Bolognese Pasta Sauce. The other is Dolmio Original Bolognese.

Illustration for How to Compare Two Foods Using the Nutrition Label

Both are tomato-based sauces intended for similar meals. Both contain tomato, herbs and added sugar. Their front labels offer different reasons to choose them.

Which is the better nutritional option?

The answer is not necessarily the one with the healthiest-looking jar, the shortest marketing message or the most impressive reference-intake percentages.

On the current published labels, both sauces contain 5.4g of sugars per 100g. Tesco's has 0.62g of salt, while Dolmio's has 0.69g. The differences are modest, but they are real.

Let's compare them properly, from the first line of the nutrition panel to the last line of the ingredients list.

Step one: make sure you're comparing similar foods

There is no point declaring a tomato pasta sauce better than a tub of Greek yoghurt merely because one contains more protein and the other less salt. Their roles in a meal are different.

For a practical supermarket comparison, begin with two foods you might genuinely choose instead of each other.

We chose:

Tesco Bolognese Pasta Sauce, 500g jar (Tesco Ireland product listing).
Dolmio Original Bolognese Sauce, 320g jar (Tesco Ireland product listing).

Both are tomato-based cooking sauces. They are not identical recipes or identical jar sizes, but they serve a comparable purpose.

We use their retailer-published nutrition information, not assumed scores or a guessed recipe.

Step two: ignore the suggested serving for a moment

The most useful standardisation on an EU food label is the per 100g or per 100ml nutrition declaration.

It gives you a consistent comparison even if one manufacturer describes a serving as 125g and another uses 160g.

In our example, Tesco's declared serving is one quarter of its jar, or 125g. Dolmio's listed portion is 160g.

If you looked only at their per-portion columns, you might assume Dolmio contains a great deal more of some nutrients. But its suggested portion is 28% larger.

That makes a direct per-serving comparison unfair.

Compare per 100g first. Then apply the portion you will actually eat.

The real nutrition comparison

The following figures come from the two Tesco Ireland product records. Both are per 100g of sauce, as sold.

Nutrient	Tesco Bolognese	Dolmio Original Bolognese
Energy	39 kcal	45 kcal
Total fat	0.7g	0.6g
Saturated fat	0.1g	0.1g
Carbohydrate	6.0g	7.9g
Of which sugars	5.4g	5.4g
Fibre	1.7g	1.3g
Protein	1.5g	1.3g
Salt	0.62g	0.69g

Sources: Tesco Ireland listings for the exact 500g Tesco sauce and 320g Dolmio sauce. Reviewed 20 October 2026.

Several observations are worth separating.

The sugar is the same. Both products declare 5.4g sugars per 100g.

Dolmio contains slightly more salt. The difference is 0.07g per 100g, which does not by itself make the product dramatically different.

Tesco has a little more fibre. It declares 1.7g versus Dolmio's 1.3g per 100g.

Energy is similar. The difference is 6 calories per 100g.

These are not the sort of figures that justify calling one product dangerous and the other perfect. They show why measured comparisons work better than branding.

Step three: translate per 100g into a portion you might actually eat

Suppose you use 125g of each sauce for the same pasta meal.

The calculation is straightforward: take each per-100g number and multiply by 1.25.

Nutrient in an equal 125g portion	Tesco	Dolmio
Calories	about 49 kcal	about 56 kcal
Sugars	6.75g	6.75g
Fibre	about 2.13g	about 1.63g
Salt	about 0.78g	about 0.86g

These are calculations from the published values and are rounded. They do not include the pasta, cheese, mince or other ingredients in the meal.

Now we can say something accurate: in equal amounts, the sauce labels show the same total sugars; Tesco contributes a little less salt and somewhat more fibre.

A difference of roughly 0.09g salt in one equal-size serving is not the same as a major dietary effect on its own. It may still matter when considering an overall pattern of frequently eaten foods.

Why does serving size create confusion?

A pack's suggested serving is not a universal serving-size law for all products in that category.

Manufacturers choose a serving for their packaging, subject to applicable food-information rules. Competitors may choose different weights.

The best way to avoid confusion is to perform two comparisons: per 100g for a consistent baseline and per actual portion for your own meal.

This is especially useful for cereals, granola, sauces, protein bars, flavoured yoghurts and drinks.

Step four: check what “sugars” actually measures

Both pasta sauces declare 5.4g of total sugars per 100g.

Does that mean they contain exactly the same amount of added sugar?

No.

The EU nutrition declaration lists total sugars. It does not have a mandatory separate line showing precisely how much sugar the manufacturer added.

Tomatoes naturally contain sugars. Both products also list sugar as an ingredient.

The nutrition panel combines the naturally present sugars with those added during manufacture.

Therefore, the label does not allow us to calculate the exact added-sugar amount from the total alone.

Why we shouldn't call sugar in tomato sauce “hidden”

Sugar is not hidden when it appears in the ingredient list.

But its presence can be easy to overlook because pasta sauce is not usually thought of as a sweet food.

A better approach is to ask whether sugar was added, how much total sugar the product contains, and what a normal portion contributes.

For our two sauces, both the presence of added sugar and the total 5.4g-per-100g sugar figure are visible.

The precise added-sugar amount is not supplied.

Step five: compare the salt properly

Salt matters because regular high intakes are associated with raised blood pressure and cardiovascular risk.

In Ireland, the HSE advises adults to limit salt, commonly expressed as no more than 6g per day.

The EU food label gives salt in grams, not sodium in milligrams. For labelling, salt is calculated as sodium multiplied by 2.5, even when some sodium comes from ingredients other than table salt.

For the 125g sauce portions:

Tesco: approximately 0.78g salt.
Dolmio: approximately 0.86g salt.

These amounts are only the sauce component of a meal.

Add grated cheese, salted cooking ingredients or a seasoned meat product and the total will change.

The sensible lesson is not that 0.07g per 100g proves one jar is bad. It is that salt can accumulate across several foods in a meal and throughout the day.

Would a “low salt” claim apply?

Under EU nutrition-claim rules, a low-salt food generally needs no more than 0.3g salt per 100g (or the equivalent sodium threshold), subject to the regulation's conditions.

Neither of these two sauces meets that threshold based on the listed figures.

That fact should not be confused with a complete judgement about a balanced meal or an individual's health.

Step six: read the ingredients, then their percentages

Now turn from the nutrition table to the ingredients.

Tesco Bolognese Pasta Sauce

The listed ingredients begin:

Tomato (67%), tomato purée (24%), sugar, onion, cornflour, sunflower oil, salt, followed by onion powder, concentrated lemon juice, herbs and garlic purée.

Dolmio Original Bolognese

The listed ingredients begin:

Tomatoes (78%), tomato paste (10%), onion, sugar, modified maize starch, salt, sunflower oil, followed by basil, garlic, citric acid, parsley, herbs and spices.

A few things become clear.

Both start with tomato ingredients. Both include sugar and sunflower oil. Both use starch-based ingredients for texture. Dolmio lists an acidity regulator, citric acid.

The ingredient order gives useful context because ingredients are generally listed in descending order of their weight when used.

But the percentages also need careful interpretation.

Can you add the tomato percentages and declare a winner?

Not reliably.

Tesco lists 67% tomato and 24% tomato purée. Dolmio lists 78% tomatoes and 10% tomato paste.

Tomato purée and tomato paste are concentrated ingredients that differ from ordinary tomatoes in water content. Simply adding those percentages and comparing the totals as though the ingredients were identical is not a sound nutritional calculation.

The labels tell you how much of those declared ingredients were used under the relevant rules. They do not by themselves tell you the final fresh-tomato equivalent or prove that one sauce tastes better.

For a measured decision, use the percentages as composition information, not as a single score.

Step seven: don't panic at every unfamiliar ingredient

Dolmio lists citric acid as an acidity regulator. The Tesco sauce lists cornflour.

An unfamiliar additive name is not, by itself, evidence of harm.

Citric acid can be used to adjust acidity. Starches can change consistency. Ingredient names describe their function, but the complete food still needs to be judged in context.

Likewise, fewer ingredients do not necessarily translate into fewer calories, lower salt or higher fibre.

If an ingredient is important to you because of an allergy, intolerance or another specific reason, the exact label matters much more than a generic “natural” impression.

Use our ingredients-list guide for the rules behind ingredient order, emphasised allergens and declared percentages.

Step eight: decide whether the differences justify changing what you buy

It is tempting to take a table like this and name a winner.

Our comparison supports something more useful.

For these specific label versions:

Total sugar is identical per 100g.
Tesco has modestly less salt.
Tesco has slightly more fibre.
Dolmio has slightly fewer total fat grams, although the values are low in both.
The tomato ingredients and seasonings differ.
Their jar sizes and suggested portions differ.

The Tesco product's per-100g nutrition is somewhat more favourable on several measures in this comparison. But that is not an overall Sláinte Score, a clinical evaluation or a claim that the difference will produce measurable health benefits.

Taste, allergies, recipe requirements, budget and how much sauce you use are legitimate considerations too.

The value of this exercise is that you can explain why one option might suit you rather than relying on the brand or packet colour.

What about price?

Price is useful to compare, but use the price per kilogram, not just the price printed for jars of different sizes.

Prices and promotions change quickly. In the retailer listings reviewed for this example, the jars differ substantially in size and listed unit price; do not copy those prices into evergreen article claims unless you plan to keep them updated.

A higher price is not proof of a better nutrition profile.

What if the two products aren't quite the same size or flavour?

Start with the most comparable products available.

If there are still differences, declare them openly.

Comparing plain yoghurt with another plain yoghurt is usually clearer than comparing plain yoghurt with a strawberry dessert. Comparing two Bolognese sauces is generally fairer than comparing a ready-to-eat pasta meal with concentrated pasta paste.

When serving sizes differ, standardise per 100g first.

When formulations differ, read both ingredient lists before drawing conclusions.

And when an important nutrient isn't declared, don't fill the gap with a guess. Fibre may be absent from some labels because it is not part of the mandatory seven-line nutrition declaration.

Missing information is not the same thing as zero.

The 30-second comparison to use in any Irish supermarket

This is the routine worth remembering:

Same category: compare products that do the same job.
Same baseline: read every nutrient per 100g or 100ml.
Check the main trade-offs: sugars, saturated fat, salt, fibre, protein and energy, according to the food category.
Read ingredients: identify dominant ingredients, added sweeteners, oils, allergens and important percentages.
Use your actual portion: multiply the label figures by your real serving weight.
Make a decision: consider nutritional differences alongside taste, price and dietary needs.

No complicated calculation is needed for most products.

But if you're comparing a particular ingredient or trying to reduce one nutrient, taking an extra 30 seconds is often worthwhile.

How Sláinte can help you compare two packs

Sláinte is designed for precisely this sort of comparison.

Its published method uses 55% nutrition, 30% ingredients and 15% processing and quality signals, with different rules for different product categories.

The nutrition component is derived from the 2023 Nutri-Score nutrient model with published Sláinte modifications; the final score also includes ingredient and processing signals and category-specific limits.

That gives you a consistent framework for interpreting more than one figure.

But barcode matching matters. A 500g Tesco Bolognese sauce and a different Tesco sauce flavour should not be treated as the same product record. A reformulated pack can also differ from an older database entry.

We have not invented Sláinte Scores for the Tesco or Dolmio sauces here. The values in this article are directly from their listed nutrition labels; actual Sláinte results should be taken from the current matching barcode records.

Read the Sláinte methodology, or scan your next food product.

Frequently asked questions

Should I compare per serving or per 100g?

Start with per 100g or 100ml to make a fair like-for-like comparison. Then calculate what your actual portion contributes.

What if two foods have different serving sizes?

Do not compare their per-serving figures directly without accounting for the weight difference. Standardise both to 100g or another equal weight first.

Is a lower sugar number always better?

Not in isolation. Check fibre, ingredients, calories, saturated fat and the role of the food in your diet. Total sugars also include naturally occurring sugars.

Why can salt appear when there is no table salt in the ingredients?

EU food labels calculate salt from sodium, multiplied by 2.5. Sodium from ingredients other than table salt contributes too.

Does the first ingredient make up more than half the food?

Not necessarily. It is generally the largest individual ingredient by weight when used, but it can be less than 50%.

Are tomato purée and tomatoes equivalent when listed as percentages?

No. Purée or paste may be concentrated and differs in water content from ordinary tomatoes. Do not add the numbers and interpret them as directly equivalent fresh-tomato percentages.

Does fewer ingredients mean healthier?

No. A shorter list makes composition easier to understand but does not replace the nutrition table.

Can I tell how much added sugar is in a sauce?

The standard EU nutrition table declares total sugars, not a separate mandatory added-sugars figure. The ingredients list can show that sugar is added, but not its exact amount unless further information is supplied.

Which sauce scored better with Sláinte?

This article does not assign either product a Sláinte Score. A genuine score needs the exact matching barcode, current verified data and the live scoring engine.

The short version

Compare products serving the same purpose.
Start with the legally standardised per-100g figures.
Tesco and Dolmio Bolognese both list 5.4g sugars per 100g.
Tesco lists 0.62g salt; Dolmio lists 0.69g.
Equal 125g portions have approximately 0.78g and 0.86g salt respectively.
Different manufacturer's serving sizes can exaggerate apparent differences.
Total sugars are not a direct measure of added sugars.
Ingredient order and percentages help explain composition.
Concentrated tomato ingredients cannot be treated as identical to fresh tomatoes when comparing percentages.
Product labels can change, so the physical pack remains the final reference.

Keep reading

Sources

Last reviewed: 18 October 2026