How the Osana food score works

In the app, each score comes with a color and a label. You don't need to remember the math: the label tells you where a product stands.

An example from the breakfast aisle

Here are five breakfast products, one for each band, with the score Osana gives them today. Same aisle, same morning routine, very different results.

Every product starts with 100 points. We then take points off in four areas, each with its own maximum. Nutrition weighs the most, because what the food contains matters more than anything else. Additives and processing come next, and a small part of the score reflects your own preferences.

Score = 100 − nutrition − additives − processing − preferences

The numbers above are maximum penalties, not percentages. They add up to more than 100 on purpose: a product can have problems in every area at once, and the score should show it. The final result is always kept between 0 and 100.

To judge nutrition, we use Nutri-Score, a rating system built by public-health researchers and printed on packaging across much of Europe. We chose it because it has been studied for years, it is fully public, and it looks at the whole product rather than a single nutrient.

Nutri-Score looks at 100 g of the product, the same way for every food, and weighs the nutrients you should limit against the ones you should eat more of. Most of these numbers come straight from the Nutrition Facts label you already know.

From grade to points

The result is a grade from A to E. We turn that grade into a penalty. The penalty rises faster from C onward, so a product that is poor on nutrition can't end up with a good score just because it has no additives.

When we only know the letter and not the exact value, we use a fixed number in the middle of each range: 5 for A, 15 for B, 30 for C, 48 for D and 62 for E. When a product has no nutrition data at all, we take off 40 points rather than giving it the benefit of the doubt.

Additives are the colors, preservatives, sweeteners and texturizers added to packaged food. Most are harmless, some are worth limiting, and a few have been banned or restricted. Lumping them together would not be fair, so we rate each one individually.

Our reference list covers more than 80 additives common in US grocery stores. We match them both by E-number and by the names printed on American labels, like “Red 40” or “sodium nitrite”. Each additive falls into one of four tiers.

The points add up for each additive in the product, up to a maximum of 30. An additive we don't have data on yet counts as low risk (1 point) until we review it.

Why some additives are rated high risk

• Red 3 lost its FDA authorization in January 2025, and brominated vegetable oil was banned by the FDA in 2024.
• Potassium bromate, used in some flours and breads, is banned in California from 2027 under the California Food Safety Act.
• BHA, a preservative, is listed by the National Toxicology Program as reasonably anticipated to be a human carcinogen.
• Aspartame is still approved by the FDA, but it was classified as a possible carcinogen in 2023. Until the evidence is clearer, we prefer to be cautious.
• Nitrites and nitrates, used to cure bacon, ham and hot dogs, can form cancer-linked compounds during digestion and cooking.

Why some are rated moderate

In 2025, the FDA announced a plan to phase out petroleum-based synthetic dyes from the US food supply, including Red 40, Yellow 5 and Yellow 6. These dyes are still widely used, especially in foods marketed to children, so we flag them. Some emulsifiers, like carrageenan and polysorbate 80, are also in this tier because research suggests they may irritate the gut.

Two products can have very similar nutrition labels and still be made in completely different ways. A bowl of oats and a box of oat-flavored cereal puffs are not the same food. To capture that, we use NOVA, the most widely used system for classifying foods by how processed they are.

1. 1

   Unprocessed or minimally processed

   Fresh fruit and vegetables, eggs, plain milk, rolled oats, dried beans

   −0
2. 2

   Culinary ingredients

   Olive oil, butter, sugar, salt, flour

   −3
3. 3

   Processed foods

   Cheese, canned beans, bakery bread, salted nuts

   −10
4. 4

   Ultra-processed foods

   Soda, chips, sweetened cereals, packaged snacks, hot dogs

   −20

Ultra-processed foods are made mostly from ingredients you would never find in a home kitchen: protein isolates, modified starches, flavorings, emulsifiers and colors. They are designed to be cheap, shelf-stable and very easy to overeat. When we can't determine the group, we take off 10 points.

When you set up the app, you can tell us what you try to avoid. Each preference that applies to a product takes 5 points off, up to 10 in total. If you skip this step, this part of the score stays at zero.

This is why two people can see a different score for the same product. We keep this part small on purpose: your preferences should tailor the score, not overturn it. If you eat gluten-free, our gluten free scanner guide explains how the app helps.

Let's put it all together with a typical sweetened breakfast cereal, scanned by someone who chose to limit sugar. The product is illustrative, but the math is exactly what the app does.

Take out the two dyes and BHT, and the cereal gains 12 points but stays in the Poor range, because its nutrition and processing haven't changed. Switch to plain rolled oats, with no additives and minimal processing, and you land in the 90s. That side-by-side comparison is exactly what the score is built for.

The score works best as a quick comparison tool. A few habits make it more useful:

• Compare within the same aisle. A score is most helpful when you're choosing between two breads or two yogurts, not between a bread and a soda.
• Look at the reasons, not just the number. Tap a product to see what lowered its score. A few points lost to salt is not the same as a high-risk additive.
• Aim for better, not perfect. Moving from a Poor to an Average pick on the products you buy every week makes a real difference over time.
• Use the alternatives. When a product scores low, the app suggests higher-scoring options in the same category. See our top-ranked foods for inspiration.

No single number can capture everything about food. We would rather be upfront about the limits than oversell the score.

• It looks at 100 g, not your serving. Foods you eat in tiny amounts, like mustard or hot sauce, can look worse than their real impact on your diet.
• It doesn't know your health. Allergies, pregnancy, diabetes or kidney disease call for advice from a doctor or dietitian, not a general score.
• People react differently. Additive ratings reflect evidence across the population. Some people are sensitive to ingredients we rate as low risk.
• Data can be incomplete. Recipes change and databases take time to catch up. When in doubt, the package in your hand is the reference.
• It judges products, not diets. A low-scoring treat can have a place in a balanced diet. The score is there to help you choose, not to make you feel guilty.

Ingredient lists and nutrition facts come from open food databases such as Open Food Facts, from brand data and from community contributions. Our additive ratings follow public guidance from US agencies like the FDA and the NIH, along with peer-reviewed research.

We review the additive list whenever a regulator changes its position, for example when the FDA revokes an additive. When the method itself changes, we update this page and the date at the top.

Osana is independent. Brands can't pay for a better score, a ranking or a placement, and we don't use affiliate links, so we earn nothing when you buy a product. The app is funded by the people who use it.