Category: Tips

Stumped by whether to look at “Per 100 g” or “Per serving”?

Confused about nutrition labels on foods?

Stumped by whether to look at “Per 100 g” or “Per serving”? Baffled by what the figures actually mean? Well, you’re not alone. But luckily, you don’t have to be a food scientist or Nutritionist to get your brain around the labels, and by the end of this article, you will (hopefully) be making wiser and more informed food choices when it comes to your weekly shop. This quick guide covers how to read nutrition labels, including how to compare per-100 g information with the serving size on nutrition labels so you can make practical choices.

Summary

This guide explains how to read UK nutrition labelling, using “per 100 g” for fair product comparisons and “per serving” to estimate what you’ll actually consume. It clarifies that back‑of‑pack nutrition declarations are mandatory while front‑of‑pack traffic‑light labels are voluntary and simplified. Key tips include watching for low‑fat products with added sugar, sanity‑checking small portion sizes, and scanning the ingredients list (ordered by weight) for high sugar or fat. In short: compare by 100 g; plan by serving.

The legal bit…

Food packaging is highly controlled and strictly regulated, and companies cannot go around putting any old jargon on their products. There is a list of mandatory requirements that a supplier must display on their packaging (such as the name of the food, a list of the ingredients, allergen information and so on…). Under food labelling laws UK, these rules help standardise what you see and protect consumers.

As of December 2016, declaring nutritional content on products was no longer on a voluntary basis, and “all companies supplying pre-packaged foods to consumers must, by law, provide a ‘nutrition declaration’ on the back of packaging”. ‘Front of pack’ labelling is still on a voluntary basis, and the new law allows companies to repeat nutrition declarations on the front of their packaging. The idea behind this is to provide at-a-glance nutrition information, so that the busy consumer can make a speedy but informed dietary decision. A little confused? Bear with…

When it comes to our diets, we, as consumers, are becoming increasingly short on time and increasingly reliant on convenience. For this reason, there have been some significant changes to the layout of nutrition labels. This is where the traffic light system (often called traffic light food labels) comes into play, and allows consumers to make quick decisions on the “healthiness” of foods they are buying. This is all well and good, but is the decision informed and understood? Do shoppers know why these foods are “Green” for sugar but “Red” for fat content? And can they be relied upon solidly for making healthier choices?

Did you know…

• Low Fat foods are often replaced with sugar; fat is tasty, and when it is removed it needs to be replaced with something equally as appetising — calling sugar! This is a common low fat high sugar trade-off to watch for when scanning labels.
• Nutrition declarations are mandatory on the “back of pack” labelling, but voluntary on “front of pack”. Most companies will display front of pack labelling, but TOP TIP if there is no nutrition information on the front of pack it would be recommended to turn over and have a read.
• Not everything needs to have a nutrition label — exemptions include fresh fruit and vegetables that have not been prepared, herbs and spices, tea and coffee, flours, some vinegars, and any drink with an alcoholic strength above 1.2%.

Top tips…

• The traffic light system is very black and white (or red, amber, green…) — in other words, it allows consumers to make a “yes” or “no” food choice without considering any of the other nutritional values of a food. High fat does not necessarily mean bad, and conversely, a food that is low in fat does not necessarily mean it is the healthier option. Take low fat yoghurt, for example — Tesco Greek Style Natural Yogurt contains 9.5 g of Fat and 5.4 g of Sugar per 100 g; the Low Fat version contains one third of the amount of fat, but comes in at 7 g of sugar per 100 g.
• Calories aren’t the only measure of whether a food is healthy or not.
• Remember to look at the serving suggestion — don’t be fooled into thinking that “per 100 g” is the serving size. Equally, portion sizes are often a lot smaller on packs than in reality (who realistically only has 30 g of cereal in the mornings…). Comparing per 100 g to the stated serving size on nutrition labels is key to fair comparisons between products.
• The ingredients list on the back of the packaging is listed in order of weight/quantity; i.e. the first ingredient in the list is present in the largest amount. In other words, ingredients listed by weight means the first item dominates the recipe. So if the first ingredient is sugar, you can pretty much go ahead and put it back on the shelf.

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Q&A

Question: Should I look at “per 100 g” or “per serving” on a nutrition label?

Short answer: Use “per 100 g” to fairly compare different products (since serving sizes vary), and use “per serving” to estimate what you’ll actually eat. Always sanity‑check the stated portion size—if you typically eat more than the suggested serving, scale the numbers up to your real portion.

Question: What’s the difference between back‑of‑pack and front‑of‑pack labels?

Short answer: Back‑of‑pack nutrition declarations are mandatory in the UK (since December 2016) and give the full detail. Front‑of‑pack traffic‑light labels are voluntary, simplified repeats meant for quick decisions. They’re helpful for a glance, but they can oversimplify—so turn the pack over to see the full picture.

Question: Can I rely on traffic‑light colours to judge if a food is healthy?

Short answer: Use them as a guide, not a verdict. A red for fat isn’t automatically “bad,” and a green for sugar doesn’t make a food universally “good.” Check the full nutrition table and ingredients, and remember calories aren’t the only measure of healthfulness.

Question: Why might “low fat” foods have more sugar?

Short answer: When fat (which adds flavour and texture) is removed, manufacturers often add sugar to keep the product appealing—a common low‑fat, high‑sugar trade‑off. For example, a Greek‑style yogurt may drop fat but raise sugar per 100 g. Always compare per‑100 g sugar and read the ingredients list.

Question: How can the ingredients list help me spot high sugar or fat?

Short answer: Ingredients are listed by weight, so the first item is present in the largest amount. If sugar appears first (or very early), the product is likely high in sugar; likewise for fats/oils. Use this alongside the per‑100 g values to judge what you’re really choosing.

Question: Do all foods need a nutrition label?

Short answer: No. Exemptions include unprepared fresh fruit and vegetables, herbs and spices, tea and coffee, flours, some vinegars, and drinks with more than 1.2% alcohol. Most other pre‑packaged foods must carry a back‑of‑pack nutrition declaration.

Check out – Nutritious Dinner Recipes for Busy Weeknights

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