How to read a food label like a scientist

Food safety

A food label is two things at once: real information and marketing. The skill is telling them apart. Once you know where the facts are and where the persuasion is, you read a label in seconds — and you make better products, because you know what your own label is really saying.

1. The ingredients list is ranked by weight

Ingredients are listed from most to least. Whatever is first makes up the largest share. This one rule tells you a lot — if sugar or oil sits near the top, that is what you are mostly buying.

Watch for split sugars. Sugar can appear under many names — cane sugar, glucose syrup, dextrose, fruit juice concentrate. Split across several names, each sits lower in the list, even when sugar is really the main ingredient.

2. Nutrition numbers: check “per 100 g” vs “per serving”

Nutrition information may be given per 100 g or per serving. A “serving” can be made small to make the numbers look better. To compare two products fairly, always compare the per 100 g column — it is the honest, like-for-like measure.

3. Some claims are regulated; many are just words

Specific, measurable claims usually have rules behind them. Vague, feel-good words often mean nothing:

Usually meaningful — “no added sugar”, “source of fibre”, a specific weight or percentage.
Often just marketing — “natural”, “premium”, “traditional”, “fresh”. These may sound reassuring but rarely guarantee anything specific.

4. Dates: quality versus safety

There are two kinds of date, and they mean different things:

“Best before” — a quality date. After it, the food may lose flavour or texture but is usually still safe.
“Use by” — a safety date, used on perishable foods. Do not eat these after the date.

5. Allergens should be clear

This is the line that protects people. Common allergens — peanuts, tree nuts, shellfish, fish, egg, milk, soy, wheat/gluten — must be easy to find. If you cannot quickly tell whether a product contains an allergen, that is a poorly made label, and on your own products it is a serious risk to fix.

6. Net weight, producer, and additives

Three quieter but important items:

Net weight or volume — how much you actually get, and the honest basis for comparing price.
Producer name and contact — a real, contactable maker is a sign of a trustworthy product.
Additives — preservatives, colours, and stabilisers are listed too. Not all are bad; many make food safer or last longer. The point is that they are declared, not hidden.

The short version

Ingredients are ranked by weight — the first one dominates.
Compare nutrition per 100 g, not per serving.
Specific claims mean something; “natural” and “fresh” usually don’t.
“Best before” = quality; “use by” = safety.
Allergens must be clear; net weight and producer should be too.

A note on this article. This is general educational information. Labelling rules differ by country and product — if you are making a label to sell in Cambodia, follow the current national requirements (for example, the Cambodia Standard for food labelling) and confirm the details with the relevant authorities.