How to read a nutrition label
Start with the column heading, not the calories. Gulf labels may give the figures per 100 g, per 100 ml or per a serving the manufacturer defines, and every line below refers to whichever it is[1]. Use the per-100 g column to compare two products, and the per-serving column only after checking that its serving resembles your portion. The energy figure is calculated from the declared nutrients, not measured, and food law allows it a defined margin.
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What the panel is actually telling you
A nutrition panel on a packaged food sold in the Gulf has to declare five things: carbohydrate, fat, protein, dietary fibre and energy, with energy expressed in kilocalories. The figures may be set out per 100 g or 100 ml of the product, or per serving as the manufacturer defines it[1]. Everything else on the box, from the word "light" to the photograph of someone running, is marketing governed by other rules. The panel is the part written to a standard, and it is the only part worth reading closely.
Which means the first thing to find on a label is not a number. It is the column heading, because the heading decides what every number underneath it refers to.
Serving size is the line people misread
A serving is whatever the manufacturer declares it to be, and the regulator says so plainly: the serving size is not a recommendation of how much you should eat[4]. It reflects an amount people are assumed to consume in one sitting, which may be a third of the bag in front of you or twice what you would actually take.
Every figure in the panel then hangs off that choice. A juice carton declaring its sugars per 250 ml and a carton declaring them per 200 ml are not telling you different things about the juice; they are telling you the same thing in two frames[1]. This is why the per-100 g or per-100 ml column is the one to use when you are comparing two products on a shelf, and the per-serving column is the one to use only after you have checked that its serving resembles the portion you are about to eat.
The habit worth building is mechanical. Read the serving size, decide what multiple of it you are having, and apply that multiple to every line.
The calories were calculated, not burned in a laboratory
The energy figure is not usually measured. Under European rules it is computed from the declared nutrients using fixed factors: 4 kcal per gram of protein and of carbohydrate, 9 kcal per gram of fat, 2 kcal per gram of fibre, 7 kcal per gram of alcohol, 2.4 kcal per gram of polyols and 0 kcal per gram of erythritol[2].
Two things follow from that. The first is that you can roughly rebuild the energy line yourself from the macronutrients, and if it will not rebuild, the difference is usually fibre, a polyol sweetener or alcohol. The second is that a product reformulated to swap sugar for a polyol loses energy on the label by arithmetic, before anyone has eaten it.
How wrong a label is allowed to be
A declared figure is a declaration about a production run, not about the packet in your hand, and food law builds that in. European guidance for enforcement authorities accepts, for protein, carbohydrate, fat, sugars and fibre, a difference from the declared value of 1.5 g where the food holds less than 10 g per 100 g, 15% where it holds between 10 and 40 g per 100 g, and 6 g above that; for salt at or above 1.25 g per 100 g the accepted difference is 20%[3].
Rounding widens the gap at the small end. Where a label follows the United States rules, a serving of 50 calories or fewer is rounded to the nearest 5, anything above that to the nearest 10, a serving under 5 calories may be declared as zero, and fat under 0.5 g per serving may be printed as 0 g[6]. That is how a cooking-oil spray is sold as zero-calorie: the spray is fat, and the declared serving is small enough to round away. Ten sprays are not zero.
None of this makes labels useless. It makes them good to within a few per cent on a single item and very good across a week of many items, which is the level of precision a calorie target needs anyway.
Percent Daily Value, and who it was written for
The %DV column answers a question you did not ask: how does this serving compare to a reference day of 2,000 calories[4]? The reference values behind it are fixed — 2,300 mg of sodium, 50 g of added sugars, 28 g of dietary fibre, 20 g of saturated fat and 50 g of protein a day — and the rule of thumb is that 5% DV or less of a nutrient per serving is a little and 20% or more is a lot[5].
It is useful for sodium and added sugars, where most people's limit really is close to the reference. It is misleading for energy and protein, where your own figure is personal. If your target came from your body rather than from a reference day, read the grams and the kilocalories and ignore the percentages. The guide on how your daily calories are calculated sets out where a personal figure comes from, and how to split your calories into carbs and fat explains what to do with the macronutrient lines once you have one.
When half of what you eat carries no label
This is the part a label guide usually skips. Bread from the bakery, foul and taameya from the cart, koshari, machboos cooked in a family pot, shawarma carved to order: none of it has a panel, and in most Arab kitchens that is the larger share of the day. Packaged food is where labels help, and the honest use of them is to pin down the items you buy repeatedly — the oil, the bread, the yoghurt, the biscuits, the juice — so that the estimating you cannot avoid is confined to the cooked dishes.
For those, a reference portion and a consistent method beat a precise number you do not have. Logging the labelled items from the pack and the cooked ones by household measure in the same place is enough to keep a week readable, and a calorie counter that works in Arabic will take both in the same sentence.
Sources
- GCC Standardization Organization. GSO 9/2013: Labeling of Prepackaged Food Stuffs, clause 5.3 (Nutritional Information). Technical regulation, approved 2 October 2013. ↩
- Regulation (EU) No 1169/2011 on the provision of food information to consumers, Annex XIV: energy conversion factors. ↩
- European Commission, Health and Consumers Directorate-General. Guidance document for competent authorities for the control of compliance with EU legislation … with regard to the setting of tolerances for nutrient values declared on a label, 2012, section 4. ↩
- US Food and Drug Administration. How to Understand and Use the Nutrition Facts Label. ↩
- US Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels. ↩
- US Code of Federal Regulations, Title 21, §101.9(c)(1)–(2): nutrition labelling rounding rules for calories and fat. ↩