How to read a food label in 15 seconds: a smart shopper's guide

Quick answer: To read a food label fast, ignore the front of the pack and turn it over. Check three things: (1) the ingredient list, which is ordered by quantity, so the first 2–3 ingredients are most of the product; (2) added sugar and sodium per 100 g; and (3) the serving size. Comparing products "per 100 g" is the quickest way to spot the healthier choice.

"Baked, not fried." "Multigrain." "No added sugar." "Protein-rich." Front-of-pack claims are marketing. The truth is on the back, and once you know where to look, it takes about 15 seconds.

The 15-second label check

Seconds 1–5: read the first three ingredients

Ingredients are listed from most to least by weight. If sugar, refined white flour or palm oil is in the first three, that's mostly what you're eating, whatever the front says. Watch for sugar's many names: invert syrup, glucose, maltodextrin, fructose, cane sugar and "liquid glucose".

Seconds 6–10: check sugar and salt per 100 g

Most labels show nutrition per 100 g (or 100 ml), per serving, or both, and many countries now require added sugars to be listed separately. A rough rule of thumb:

• Added sugar: over 22.5 g per 100 g is high, and 5 g or less is low.
• Sodium: over 600 mg per 100 g is high, and 120 mg or less is low.
• Saturated fat: over 5 g per 100 g is high, and 1.5 g or less is low.

Seconds 11–15: check the serving size

A "per serving" figure can look small because the serving is tiny, like 3 biscuits when most of us eat 8. Multiply by what you'll actually eat.

Common label traps

• "Multigrain" or "whole wheat" often still lists refined flour first.
• "No added sugar" can still mean a lot of natural sugar, as in fruit juices.
• "Baked" snacks can be as high in salt and fat as fried ones.
• "High protein" bars can carry as much sugar as a chocolate bar.
• "Sugar-free" sweets may be high in fat or use sugar alcohols that upset some stomachs.

Quick symbols to know

• Vegetarian or vegan marks: useful if you avoid animal foods, but they say nothing about how healthy the product is.
• Registration or licence number: shows the maker is registered with the national food safety regulator.
• "Best before" vs "use by": best before is about quality, while use by is about safety.

What's changing

Food regulators in many countries are moving towards clearer labels: sugar, salt and saturated fat in bold, larger print, and warning symbols or colour codes on the front of packs high in added sugar, salt or fat. Until those reach everything you buy, your 15-second back-of-pack check is your best tool.

Practise on your next shop

Compare two brands of the same product, such as two cereals or two bags of crisps, per 100 g. You'll be surprised how different "similar" products are. If you're managing diabetes, blood pressure or kidney disease, ask a dietitian which numbers matter most for you.