Why food labels can feel like a test you didn't revise for

You pick up two tubs of yoghurt, turn them over, and suddenly you're comparing six numbers, three percentages and an ingredients list longer than your shopping list. It's no wonder plenty of us give up and choose on price, packaging or habit instead.

Here's the reassuring part: you don't need to understand every figure. Food labels are there to help you make a quick decision, not to be studied like an exam paper. Once you know which two or three things to look at, most of the work is done in seconds.

This isn't about turning every meal into a maths lesson. It's about a few simple habits that make the weekly shop easier — so you can get on with the things that matter, like a walk after lunch or cooking something you actually enjoy.

Start with the front of the pack

Most UK supermarket products carry front-of-pack nutrition information, often called traffic light labelling. It shows the amount of fat, saturates, sugars and salt in a portion, with a colour beside each one.

• Green means the food is low in that nutrient — a good everyday choice.
• Amber means it's neither high nor low. Most foods sit here, and that's perfectly fine.
• Red means it's high. Worth having less often, or in a smaller amount.

As a rough guide for 100g of a food: sugars are low below 5g and high above 22.5g; saturated fat is low below 1.5g and high above 5g; salt is low below 0.3g and high above 1.5g. You don't need to memorise these — the colours do the work for you.

A practical trick is to aim for a mix. A product with three greens and one amber is generally a solid pick. One with a couple of reds is fine now and then, especially if you're having a smaller portion or balancing it out across the rest of the day.

The portion on the pack isn't always your portion

This is where labels can quietly mislead. The traffic lights are usually based on a portion the manufacturer suggests, and that portion may be smaller than what actually lands in your bowl.

Use the "per 100g" column when comparing two products — that's the fairest like-for-like comparison. Then look at "per portion" to see how it fits your plate. Cereal packets are a classic example: a 30g serving looks modest next to a real bowlful.

Reference intakes, or RIs, can help here too. They're a rough guide to how much energy, fat, saturates, sugars and salt an average adult needs across a day. If a ready meal provides 45% of your RI for salt, that's useful to know before you reach for the seasoning.

Three numbers worth your attention

If you're going to focus anywhere, focus here. These are the three most of us in the UK eat too much of, and they're linked to long-term heart health.

• Sugar: look at "of which sugars" on the back. It includes sugars naturally present in fruit, milk and yoghurt as well as added sugar, so check the ingredients list for syrups, honey, glucose, fructose and fruit juice concentrate.
• Salt: sometimes listed as sodium. To convert, multiply sodium by 2.5. Bread, sauces, stock cubes, cheese and cured meats are common hidden sources.
• Saturated fat: the figure to watch rather than total fat. It's high in butter, cream, cheese, fatty meats, pastries and many biscuits.

You're not looking for zero. You're looking for the option that's a little lower, most of the time.

A few words on claims

Phrases like "no added sugar", "low fat" or "source of fibre" have legal definitions, but they only tell part of the story. A low-fat yoghurt can be high in sugar; a no-added-sugar cereal bar can still be sticky-sweet from dried fruit and syrups.

The ingredients list is your friend here. Ingredients are listed by weight, largest first, so if sugar appears in the first three or four, there's a fair amount of it. If the list is long and full of things you wouldn't keep in your cupboard, that tells you something too.

A simple routine that actually sticks

Try this on your next shop and see how quickly it becomes second nature.

• Glance at the traffic lights first — it takes about three seconds.
• Compare "per 100g" when you're choosing between two similar products.
• Check the suggested portion against what you'd really eat.
• Look at sugar, salt and saturated fat, and ignore the rest unless there's a specific reason to check.
• Don't aim for a trolley of greens. A mix of greens and ambers, with the odd red, is a perfectly normal and balanced shop.

Food is one part of feeling well, and it doesn't have to be perfect. A brisk walk, some time outdoors and moving more in everyday life all matter just as much. If you've spent ten minutes reading labels and then headed out for some fresh air, you've done well.