Nutrition sources

This page lists where the numbers in PixNutri and on this website come from. We keep it current: when we add or remove a source, this page changes too.

Sources used in the app

What	Source	Used for
Photo scans	Google Gemini 3.1 Flash-Lite (AI model)	Recognising the food and estimating portion, calories, protein, carbs, fat, fiber, sugar and a 1 to 10 health score
Barcode scans	Open Food Facts	Nutrition facts per 100 g for packaged products
Barcode health score	Nutri-Score grade (via Open Food Facts)	Converting grades A, E into the 1 to 10 health score
Calorie target	Mifflin-St Jeor equation (1990)	Resting energy expenditure from sex, age, height and weight
Weight-loss pace	NHLBI clinical guidelines	Keeping the default deficit at 500 kcal/day
Protein target	ISSN position stand on protein (2017)	1.4 to 1.8 g per kg of body weight
Fat target	Institute of Medicine DRIs	27% of calories, inside the 20 to 35% range
Fasting timer	de Cabo & Mattson, NEJM 2019	The safety note shown with the timer
Vitamins & minerals	FDA Daily Values	Showing vitamin C, D, B12, iron, calcium, potassium and magnesium as a share of the daily value; the amounts themselves are AI estimates
Water goal and over-drinking warning	EFSA Dietary Reference Values for water (2010)	The daily water goal and the note that much more water isn’t better
Healthy eating tips and food scores	WHO healthy diet fact sheet	Light Day food tips (vegetables, lean protein, no added sugar or alcohol), the advice under scan results and insights
Walking and activity tips	WHO physical activity fact sheet	Walk suggestions in the Light Day checklist and daily check-in
Sleep tip	CDC, About Sleep	The Light Day tip to sleep a little earlier
Supplement tracker safety note	NIH NCCIH, Using Dietary Supplements Wisely	The advice to ask a doctor or pharmacist before starting supplements

Important: photo scans are AI estimates. The app does not currently look up each recognised food in a government food-composition database such as USDA FoodData Central. How the estimate is produced, and its limits, are described on our methodology and accuracy pages.

Sources used on this website

Our calorie tables use USDA FoodData Central (SR Legacy): each food page links to its USDA record. Our accuracy page summarises two peer-reviewed studies on dietary apps and AI photo estimation (Fridolfsson et al., 2025; Zhang et al., 2021). Each article and guide lists the sources it actually uses in its own “Sources” section at the bottom of the page.

Sources we prefer for new content

When we write new nutrition content, we start from primary scientific literature and official or institutional sources, for example:

• USDA FoodData Central for food composition
• EFSA Dietary Reference Values for European nutrient reference values
• WHO healthy diet fact sheet for general dietary guidance
• NHS Eat well for UK public-health guidance
• Peer-reviewed studies found through PubMed or Europe PMC

We only list a source on a page if that page actually relies on it. We avoid blogs, influencer content and other apps’ marketing claims as evidence. Read our full editorial policy.