How to Read Nutrition Labels With Your Phone [In Store]

Small print, big decisions

You are standing in the aisle holding two boxes of cereal, trying to work out which has less sugar. The nutrition panel is printed in tiny type, the columns are in different units on each box, and one lists a serving as 30 g while the other says 45 g. You give up and pick the one with the healthier-looking packaging.

Nutrition labels are genuinely hard to read, partly because of the print size and partly because of how they are structured. A phone helps with both.

Getting the panel readable

Nutrition panels are often printed in 6 to 8 point type, sometimes on a curved surface, sometimes in dark gray on a colored background. Here is the quick approach in a store.

1. Open a magnifier app. In LoupeLens, zoom to 3x or 4x, which is enough to make the panel look like normal print without shaking.
2. Hold the package so the panel faces you and is as flat as possible. For cans and bottles, rotate the container rather than moving the phone.
3. Turn on the flashlight if the panel is on dark packaging or the shelf lighting is poor. Dim the flashlight by pressing and holding and swiping if it glares off plastic film.
4. Tap the screen to take a photo when you have the panel in view. Then you can put the package down, pinch into the photo, and compare it to the second product's photo side by side.

Photographing both panels and comparing them on screen is faster than flipping two boxes back and forth. It also lets you review your choices at home.

Per 100 g versus per serving

This is the single most useful habit. Serving sizes are chosen by the manufacturer, and they vary widely between brands of the same product. A per-serving column can make a product look lower in sugar simply by declaring a smaller serving.

Most labels include a per 100 g (or per 100 ml for drinks) column, and in many countries it is required. US Nutrition Facts labels show per-serving values only; to compare products, divide each value by the serving size in grams. Use that column and only that column when comparing two products. Per 100 g, the numbers are directly comparable regardless of how the packages define a portion.

Per serving is still useful for one thing: estimating what you actually eat. If the serving is 30 g and you know you pour 60 g, double everything.

Finding the sugar

The nutrition panel tells you total sugar, and often separates added sugar. The ingredients list tells you where it comes from. Ingredients are listed in descending order by weight, so anything in the first three is a major component.

Sugar appears under many names. When scanning an ingredients list, treat any of these as sugar:

• Sucrose, glucose, dextrose, fructose, maltose, lactose (anything ending in -ose)
• Corn syrup, high-fructose corn syrup, glucose syrup, rice syrup, golden syrup, maple syrup, agave
• Honey, molasses, treacle
• Fruit juice concentrate, fruit puree concentrate
• Cane sugar, brown sugar, raw sugar, coconut sugar, invert sugar
• Barley malt, malt extract

A product can split its sweetener across several of these so that no single one ranks first. If you see three or four sugar names spread through the list, add them up mentally. Maltodextrin is not labeled as sugar, but it is a fast-digesting starch and worth noticing for the same reasons. For a rough conversion, 4 g of sugar is about one level teaspoon.

Sodium and salt are not the same number

Some labels list sodium, others list salt, and a few list both. Salt (sodium chloride) is only about 40 percent sodium by weight, so the conversion is:

Salt in grams = sodium in milligrams x 2.5 / 1000

When a label says 0.5 g salt per 100 g and another says 200 mg sodium per 100 g, they are the same. Bread, breakfast cereal, sauces, and cured meat are where this comparison pays off most.

Other things worth a second look

Fat and saturated fat

The total fat line gets the attention, but saturated fat is usually the one health guidance focuses on. Check both, per 100 g.

Fiber

For bread, cereal, and crackers, fiber per 100 g separates whole grain products from ones that merely look brown. Compare fiber alongside sugar, since the two often move in opposite directions.

Percent daily values

These are based on a reference adult and a reference serving. They are fine for a rough sense of high or low but are not useful for comparing two products with different serving sizes. Fall back on per 100 g.

Claims on the front

"Reduced sugar", "light", and "no added sugar" all have specific meanings that vary by country, and none of them mean low in sugar. A "no added sugar" juice is still mostly sugar. Read the panel, not the front.

A quick routine for the aisle

1. Pick up both products and find the nutrition panel on each.
2. Zoom in, photograph each panel.
3. Compare sugar, saturated fat, salt (or sodium x 2.5), and fiber, all per 100 g.
4. Glance at the first three ingredients.
5. Decide. The whole process takes under a minute once it is a habit.

If you read labels for medical reasons, such as managing blood sugar or blood pressure, the same routine works, and you may want to keep photos of the products you trust so you can find them again. If allergies are the concern, our allergen shopping guide goes deeper, and for the ingredient list itself see reading ingredient lists in the store.

Reading panels at home

At home you have more time and better light. This is the moment to check the products you buy regularly. Once you know that your usual bread has 1.1 g salt per 100 g, you can compare a new one against it quickly in the store. A photo library of your regular products, taken with a magnifier at 3x, is a surprisingly useful reference.