Tukuk-OSIgnore the Front, Read the Table
The front of a packet is advertising: "natural", "high in protein", "source of fibre", "light". None of it is regulated to mean much. The nutrition facts table on the back, however, is close to the truth, because it is required to list actual amounts. Learning to read that table in under two minutes does more for your understanding of a food than every slogan on the box combined. Start there.
First Line: Serving Size — and the Trick It Hides
Everything in the table is quoted per serving, and the serving size is chosen by the manufacturer, not by how much you eat. This is the single most common way labels mislead. A "per serving: 150 kcal" that you eat three times over is 450 kcal, and the "low sugar" claim was calculated on one small portion you never actually stopped at.
The fix is a habit: mentally convert to per 100 g (or 100 ml). Those figures — often printed alongside the per-serving column, and always the basis of comparison — let you compare any two products honestly, because 100 g of one biscuit and 100 g of another are directly comparable in a way "per serving" never is. When two labels seem to disagree wildly, check whether they are just using different serving sizes.
Calories: The 4-4-9 Rule
"Energy" is measured in kilocalories (kcal) — the "Calories" with a capital C on US labels — and sometimes kilojoules (kJ); one kcal is about 4.18 kJ. You don't need the table to trust the number: energy comes almost entirely from three macronutrients at fixed rates. Protein and carbohydrate each give about 4 kcal per gram; fat gives about 9 kcal per gram (and alcohol about 7). That is why a food high in fat is calorie-dense even when the weight looks small — fat carries more than twice the energy per gram of protein or carbs. If you want to sanity-check a label, multiply grams by these figures and see whether it roughly matches the stated calories.
The Macros: What Each Column Means
- Protein (4 kcal/g) — building block for muscle and tissue; the number people chase for satiety and lean mass.
- Carbohydrate (4 kcal/g) — the body's quick fuel. Read it with its two sub-lines: "of which sugars" and fibre. Total carbs is not inherently the enemy; a loaf of wholemeal bread and a soft drink can share carb grams with wildly different meaning.
- Fat (9 kcal/g) — split into saturated, unsaturated and (now largely banned) trans fats. Saturated fat is the one most guidelines ask you to watch, because of its link to blood cholesterol.
- Fibre — a carbohydrate your body does not fully digest; it is consistently associated with better digestion and appetite control, so a higher fibre number is a good sign, the opposite of how you read sugar.
The Line That Wasn't There: Added Sugars
Older labels lumped all sugar together, hiding the difference between the sugar naturally in fruit and the sugar poured into a sauce. Many modern labels now break out "added sugars" separately, and that is the number that actually matters for health — the World Health Organization's widely cited guidance is to keep free and added sugars well under 10% of daily energy, and ideally below. Fruit and milk sugar come packaged with fibre, water and micronutrients; added sugar comes as empty calories. When you compare two products, hunt for this line first.
Percent Daily Values: A Compass, Not a Ruler
The %DV column tells you what fraction of a notional daily intake one serving supplies. It is calibrated to a rough average, so treat it as a direction: 5% or less of a nutrient you want to limit is low, 20% or more is high. Don't try to add the percentages to 100 or fine-tune them — bodies vary enormously with age, sex and activity. Use them for quick "is this a lot or a little?" judgements, then move on.
Once you can read a label, the next question is what normal foods are actually made of. Our nutrition reference lists calories, protein, carbohydrate, sugar, fat and fibre for everyday foods — shown both per 100 g and per a typical serving, which is exactly the two-number comparison this article tells you to make — so you can check a claim on any packet against a plain figure for the food itself.