How to read a food label like a pro

A food label is one of the most honest things in the supermarket, but only if you know where to look. The front of the pack is advertising. Words like lite, natural, wholesome and no added sugar are all chosen to make you reach for it. The truth lives on the back, in a small table of numbers and a single line of ingredients that manufacturers are legally required to print. Learn to read those and you can see straight past the packaging in a few seconds.

In South Africa that back-of-pack information follows a standard format, and that helps: once you can read it on one product, you can read it on all of them. You don't need to be a dietitian or memorise anything. A short routine and a handful of numbers worth caring about will do it. Here's how to decode almost any label like you know exactly what you're doing.

Start with the serving size, where the trick hides

Before you look at a single number, find the serving size. The nutrition table usually has two columns: one per 100 g (or per 100 ml) and one per serving. That second column is the one manufacturers love, because they get to decide how big a "serving" is, and they often make it flatteringly small.

A bag of chips might list its numbers per 30 g when the bag holds 125 g and you'll eat the lot. A cereal shows figures per 40 g when a real bowl is closer to 70. Always ask two questions: what does one serving weigh, and how many will I eat in one sitting? If it's double, double every number on the label.

Read energy in kilojoules, and put it in context

South African labels lead with kilojoules (kJ), sometimes with calories in brackets (roughly one calorie to every 4.2 kJ). A number alone means little, since energy needs vary a lot with your size, sex and activity level. If you want to understand how those needs translate into weight loss, how many calories you need to lose weight walks through it properly.

For everyday shopping, glance at the per 100 g energy figure instead. It tells you how energy-dense a food is, which is far more revealing than a serving size someone in marketing chose.

The ingredients list tells the real story

By law, ingredients are listed in descending order by weight. That one rule turns the list into a truth serum: whatever appears first makes up most of the product, and the first three ingredients usually tell you what you're buying.

If a sweetener sits near the top, you're holding a sugary food no matter what the front claims. When the hero ingredient the packaging brags about (real fruit, whole grains, chicken) appears near the end, there's little of it in there. As a rough guide, a shorter list tends to mean a less processed food.

The front of the pack is an advert. The back is the truth. When the two disagree, believe the small print.

Hunting down hidden sugars

Under carbohydrates you'll find a line reading "of which total sugar". That figure includes both added sugar and sugar that occurs naturally, such as in milk or fruit. So a plain yoghurt or fresh fruit can show sugar without anything being wrong. Where it matters is in processed foods carrying added sugar you didn't ask for.

A handy rule of thumb on the per-100 g column: around 5 g of sugar or less is low, while 22.5 g or more is high. Between those, use your judgement. And watch the ingredients list, because sugar wears many disguises:

• Sucrose, glucose, fructose, dextrose, maltose: anything ending in "-ose"
• Cane sugar, invert sugar, molasses and treacle
• Fruit juice concentrate, honey, agave and the various syrups

Spreading sugar across several of these names is a common way to keep any single one from appearing near the top of the list. And remember that no added sugar is not the same as sugar-free. A fruit juice can be loaded with natural sugar and still make the first claim honestly.

Salt, saturated fat and fibre: a quick glance each

Three more numbers reward a look, all easiest to judge per 100 g:

Sodium

SA labels list sodium, not salt. To picture it as salt, multiply by about 2.5. Roughly 0.6 g of sodium (about 1.5 g of salt) or more per 100 g is high; 0.1 g or less is low. Processed meats, sauces and stock are the usual culprits.

Saturated fat

Look at the "of which saturated" line rather than total fat alone. Plenty of nutritious foods, like nuts and avocado, are high in fat but low in the saturated kind. Around 1.5 g or less per 100 g is low; over 5 g is worth noticing.

Dietary fibre

Here, higher is better. Fibre slows digestion, steadies blood sugar and helps you feel full, which makes eating in a deficit more comfortable. It's a big part of building a plate that keeps you full, so a higher-fibre bread, cereal or wrap is usually the smarter swap.

The per-100 g trick for comparing two products

This is the most powerful habit here. When you're choosing between two similar products, always compare using the per-100 g column. Never per serving, because the two almost certainly use different serving sizes, which makes that comparison meaningless.

Line two yoghurts or two cereals up side by side, look at the per-100 g energy, sugar and sodium, and pick the lower one. It takes ten seconds and cuts through every clever claim on both boxes.

Your thirty-second label routine

Put it all together and you have a check you can run without slowing your shop down:

1. Find the serving size and compare it to what you'll eat in one sitting.
2. Scan the first three ingredients, since that's most of the product.
3. Check sugar and sodium on the per-100 g column.
4. Compare against a rival product per 100 g, and choose.

One last thing worth remembering: the foods that need no label at all (vegetables, eggs, plain meat and fish, fruit, beans and lentils) are often the ones doing your body the most good. Labels are a tool for making sense of packaged food, not a scorecard for the whole trolley. And if choosing well feels like a daily battle no matter how carefully you read, that's worth a conversation rather than more willpower. A doctor-led programme can look at what's driving your appetite and, where clinically appropriate, discuss medically supervised options. You can see how it works from there.

Start on your next shop. Turn one product over, run the thirty-second check, and put it back if the small print doesn't stack up. Do that a few times and it stops being an effort.