NutriScanner®How the scoring works
What's behind every score.
How NutriScanner® reaches its scores, what they reflect, the research behind the approach, and what it can't tell you.
Why score the food
A microbiome test, often followed by a personalised plan, is one way to work on your gut health. NutriScanner offers another, simpler one, either instead or as well. The eating habits linked to a more diverse gut microbiome, such as plenty of fibre, a wide variety of plants, fermented foods and polyphenols, and less ultra-processed food, are well understood. So NutriScanner tests the food, not you, and helps you put those habits into practice every time you choose what to eat.
How a score is made
NutriScanner's scores are an assessment made by artificial intelligence against criteria that NutriScanner sets, informed by published research. They are not a fixed formula.
For packaged food, the product's ingredients and nutrition figures come from Open Food Facts, an independent public food database. Where available, the result also shows two standard measures from that database: Nutri-Score, and the NOVA processing level from 1 (unprocessed) to 4 (ultra-processed).
Some common foods are also checked against fixed rules, so that they score consistently.
Because the assessment is made fresh each time, the same food can occasionally score slightly differently.
What the colours mean
| Score | Colour | Label in the app | Meaning |
|---|---|---|---|
| 8 to 10 | Green | Very good (8), Excellent (9 to 10) | A great choice |
| 5 to 7 | Amber | Fair (5), Good (6 to 7) | Fine, with something to think about |
| 0 to 4 | Red | Bad (0 to 2), Poor (3 to 4) | Worth having only now and then |
What a good score reflects
Scores reward the things linked to a healthier, more diverse gut: fibre, a wide variety of plants, fermented foods and whole ingredients. They mark down heavy processing, added sugar and additives linked to gut irritation. The nutrition score looks at the overall balance of the food.
Further reading
NutriScanner's approach draws on a wide body of research into diet and the gut microbiome. These are some of the key studies in the field. Research in this area is developing, and several studies are small or show associations rather than proof of cause.
- Wastyk HC et al. Gut-microbiota-targeted diets modulate human immune status. Cell, 2021.
- Reynolds A et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet, 2019.
- McDonald D et al. American Gut: an open platform for citizen science microbiome research. mSystems, 2018.
- Chassaing B et al. Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome. Gastroenterology, 2022.
- Lane MM et al. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ, 2024.
- Cardona F et al. Benefits of polyphenols on gut microbiota and implications in human health. Journal of Nutritional Biochemistry, 2013.
- Li R et al. Association between gut microbiome profiles and host metabolic health across the life course: a population-based study. The Lancet Regional Health – Europe, vol. 50, 2025.
Prefer to listen? How Fermented Foods Unlock Healthspan and Longevity and Is the Microbiome the Key to a Long and Healthy Life?, on the Healthspan Orchestra podcast.
What NutriScanner® can't tell you
NutriScanner gives general nutrition and gut health information. It does not know your health history, any allergies or intolerances, or your own gut microbiome. It is not a medical device and should not be used to diagnose or treat illness. Talk to a healthcare professional before making changes to your diet, especially if you have a medical condition.
Photo and description results depend on what the analysis can see or is told. More detail, such as whether a dish is home-made, gives a more accurate score.