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DIABETES SERIES · ARTICLE 6 OF 17
Reading a food label
What the front of the box hides — and what the back of the box really says.
If you have diabetes, almost every box, bottle, jar and packet you pick up at the supermarket is talking to you. The front of the package — the bright colours, the smiling family, the words “healthy”, “lite”, “natural”, “low-sugar” — is designed to sell. The back of the package — the small grey panel with all the numbers — is regulated by law to be true.
The single biggest skill a person with diabetes can learn is to ignore the front of the box and read the back. Once you know how, no brand can mislead you again. This article teaches you how to do it in about ten minutes.
Before you read on
This is a guide to reading South African food labels. The law on what manufacturers must disclose is governed by the Foodstuffs, Cosmetics and Disinfectants Act Regulations. Detail changes from time to time. The principles in this article — what to look for, what to ignore — stay the same.
The two parts of a label that matter
Forget everything on the front of the package for a moment. The back has only two things you need to look at, and they tell you almost everything.
1. The Nutritional Information panel
A grey or white box, usually on the back or side of the package, with a list of nutrients and numbers. By South African law, it must show energy (kJ), protein, carbohydrates, total fat and sodium, per 100 g or per serving. Most also show sugars, saturated fat and dietary fibre.
2. The Ingredients list
A line of words listing what's actually in the food. Ingredients are listed in order of weight, biggest first. So the first three ingredients tell you what the food mostly IS — everything after that is in small amounts.
If you read those two things and nothing else, you'll already know more about the food than 95% of shoppers.
The serving size trick — the biggest hidden lie
Open a tin of baked beans. The label may say “per 100 g: 380 kJ, 4 g sugar.” That sounds fine.
Now look at how much is in the tin. 410 g. Most people don't eat a quarter-tin. They eat half, or the whole thing. So your actual portion isn't 380 kJ — it's 1 600 kJ. And your actual sugar isn't 4 g — it's 16 g. The numbers on the panel are accurate; the serving size is unrealistic.
This is the single most-used trick in food labelling. Cereal boxes do it (30 g serving = a thin smear in the bowl). Yoghurt tubs do it. Cold drinks do it (the 1 litre bottle “contains 4 servings”). The numbers always look smaller than what you'll actually eat.
How to defeat the serving size trick
Always look at TWO numbers: per serving AND per 100 g. The per-100 g number lets you compare products fairly. The per-serving number tells you what the manufacturer thinks is a portion (which is usually less than what you'll eat).
Then ask yourself honestly: how much will I actually eat? Multiply accordingly. A cereal box claim of “3 g sugar per serving” may turn into 9 g of sugar in your actual bowl.
The 30+ names for sugar
Manufacturers know that customers are reading labels for sugar. So they've found ways around it. If sugar were listed as the second or third ingredient, the product would look obviously bad. So they break the sugar into several different types, list each one separately by name, and push them all lower on the list.
Sugar by any other name is still sugar. Here are the names you'll see on South African labels:
Family Common label names Sucrose / table sugar Cane sugar, beet sugar, brown sugar, raw sugar, demerara, muscovado, icing sugar Glucose / dextrose Glucose, dextrose, glucose syrup, glucose-fructose syrup, corn syrup Fructose / fruit sugar Fructose, crystalline fructose, fruit juice concentrate, fruit sugar High-fructose corn syrup HFCS, high-fructose corn syrup, isoglucose Maltose / malt sugars Maltose, barley malt, malt syrup, maltodextrin Honey, syrups, “natural” sugars Honey, agave nectar, maple syrup, golden syrup, treacle, molasses, rice syrup, date syrup, coconut sugar, palm sugar “Healthier-sounding” disguises Evaporated cane juice, organic raw cane juice, sucanat, panela, jaggery, turbinado
If you see two or more of these on an ingredient list, they're spreading the sugar load across multiple names. Total it mentally. The combined amount tells you the real story.
The simple 5/20 rule for any nutrient
Most labels show numbers per 100 g — that's the easiest reference because it lets you compare different products on equal footing. For any nutrient on the panel, you can use the 5/20 rule as a quick eye test:
Per 100 g Counts as Why it matters 5 g or less Low Generally fine to choose 6–19 g Moderate Pay attention, especially if you'll eat a lot 20 g or more High Avoid or eat very small portions only
This rule works for sugar, saturated fat, and salt. So if a cereal label says “sugar: 25 g per 100 g”, you can instantly see it's a high-sugar product, regardless of what's on the front of the box.
For salt, the equivalent rule looks slightly different because labels usually show sodium, not salt:
Per 100 g Counts as Sodium: 120 mg or less (salt: 0.3 g or less) Low Sodium: 121–600 mg (salt: 0.3–1.5 g) Moderate Sodium: 600 mg or more (salt: 1.5 g or more) High
Marketing words that mean almost nothing
These appear on the front of the box. Almost all of them are either marketing terms with no legal meaning, or claims that are technically true but irrelevant. Don't trust them. Read the back.
Word on the front What it actually means Natural Almost meaningless. Sugar is natural. Cyanide is natural. Doesn't tell you anything about whether the food is healthy. Original Marketing word. No legal meaning. Lite / Light Sometimes means 30% less of something than the regular version — but “something” could be salt, fat, or alcohol. Often nutritionally similar. Lean Legally regulated for meats only (less than 10% fat). Meaningless on anything else. Family Marketing. Means nothing. Health / Wellness / Vital Marketing words. No legal meaning unless tied to a specific regulated claim. Sugar-free Legally regulated — must be less than 0.5 g sugar per 100 g. Usually means it has artificial sweetener. No added sugar Means the manufacturer didn't add table sugar. Doesn't mean the product has low sugar — fruit juice concentrate, honey or “natural” sugars may still be there. Low-fat Less than 3 g fat per 100 g. Often replaced with sugar to keep taste — check the sugar number. High-fibre Must contain at least 6 g of fibre per 100 g. This one is actually useful when present. Diabetic-friendly Not legally defined in South Africa. Use the panel to decide for yourself.
The general rule
The more health claims on the front of the package, the more suspicious you should be. Real, simple, healthy foods — eggs, beans, oats, vegetables — don't need marketing.
When a packet shouts about being healthy, the back of the package usually has a story.
What to specifically check if you have diabetes
Once you can read the panel, here's the four-number test you can run on almost any packaged food. Look at the per-100 g column:
Number What you want Why Sugar 5 g or less per 100 g (ideal); under 10 g acceptable for most foods The single biggest blood-sugar driver in processed foods Carbohydrate (total) Use this to plan portion size — every 15 g of carbs roughly equals one starch exchange The total carbs determine how much your blood sugar will rise Dietary fibre 3 g or more per serving is good, 6 g+ per 100 g is excellent Fibre slows glucose release Sodium 120 mg or less per 100 g is low; 600 mg+ is high Diabetes raises heart-disease risk — and so does too much sodium
You don't need to memorise this. Take a photo of it on your phone. Pull it up next time you're standing in the cereal aisle.
Worked example — a cereal box at the supermarket
Imagine you're standing in front of two cereals. The front of the package on Cereal A says “Healthy. High in fibre. Family-friendly.” The front of Cereal B is plain — just a picture of oats.
You flip both boxes over and look at the per-100 g panel. Here's what you might see:
Cereal A — “Healthy Family Crunch”
NUTRITIONAL INFORMATION
Energy 1 750 kJ
Protein 6 g
Carbohydrates 78 g
of which sugars 27 g
Total fat 8 g
of which saturated 3 g
Dietary fibre 5 g
Sodium 320 mg
Cereal B — Plain Rolled Oats
NUTRITIONAL INFORMATION
Energy 1 540 kJ
Protein 13 g
Carbohydrates 67 g
of which sugars 1 g
Total fat 7 g
of which saturated 1 g
Dietary fibre 10 g
Sodium 5 mg
What the panels tell you
Cereal A has 27 g of sugar per 100 g. By the 5/20 rule, that's high — over a quarter of the box is sugar. It has 5 g of fibre per 100 g, which is moderate. Sodium is moderate. The “healthy” claim on the front is, at best, misleading. For a person with diabetes, this is a fast blood-sugar spike disguised as breakfast.
Cereal B has 1 g of sugar per 100 g — very low. It has 10 g of fibre — excellent. 13 g of protein. Almost no sodium. No marketing claim on the front, because it doesn't need one. It IS healthy.
Cereal A costs more, has worse blood-sugar impact, and feels nutritious because of the front of the box. Cereal B is half the price, twice the nutrition. This is the gap that label-reading closes.
Your quick checklist at the supermarket
Five things, in order, every time you pick up a packaged food:
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1. Flip the package over. Find the nutrition information panel.
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2. Look at sugar per 100 g. Under 5 g is low, over 20 g is high.
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3. Look at sodium per 100 g. Under 120 mg is low, over 600 mg is high.
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4. Read the first three ingredients. If sugar (under any of its names) is there, choose something else.
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5. Decide based on the back of the box. Ignore the front.
It takes 20 seconds. Worth it for the rest of your life.
The bigger picture
Most of what makes diabetes hard is hidden — in foods that look fine, in claims that sound healthy, in serving sizes that bear no relation to reality. The food industry isn't going to stop using these tactics. The law sets a floor, but the law also lets manufacturers be creative with what they emphasise.
Once you can read the back of a box, you've put yourself in charge of your food again. You don't need an app, you don't need a dietitian over your shoulder, and you don't need to memorise complicated rules. You need 20 seconds, a willingness to flip the package over, and the 5/20 rule.
The next article in this series moves into a question that comes up at every clinic visit: blood sugar testing — when, why, and what the numbers really mean. It's the article that helps you understand your own readings rather than just hoping they're okay.
Where to get more help
Diabetes South Africa — diabetessa.org.za · 011 792 9888
Department of Health — search “Foodstuffs Regulations R146” for the SA legal framework if you want detail
Phila Today Eat tab — recipes that bypass the label-reading problem by being whole foods
Phila Today Diabetes Series — next: blood sugar testing — when, why and what the numbers mean
Phila Today · Article 6 of 17 in the Diabetes Series