How it works
How to read the numbers on this site
In short: where the food data comes from, how calorie targets are estimated, and why the package in your hand can matter more than the page.
In short
Use the numbers on this site as a guide. Neither the food database nor the calculator promises perfect precision.
- Food pages are based on Open Food Facts data and cleaned up before publication.
- The calculator gives a starting estimate, not a personal medical target.
- If numbers disagree, the package and your real weight trend matter more.
In more detail
What matters
Where product data comes from
The catalog is based on Open Food Facts. The database is available under the ODbL.
Before a product becomes a page, we standardize names, serving sizes, and nutrition fields so products are easier to read and compare.
How calories and macros are estimated
The calculator starts with an estimate of energy use at rest. In most cases it uses Mifflin-St Jeor, and it can switch to Katch-McArdle when body-composition data is available.
That estimate is then adjusted by activity level to get a maintenance target.
For weight loss or gain, the calculator adds a deficit or surplus based on the pace you choose. That gives a practical starting target, not a week-by-week promise.
Protein and fat use working ranges, carbs come from the calories that remain, and fiber is shown as a planning target. These are starting settings, not personalized prescriptions.
Why numbers can differ
Any formula can miss. It does not know your true daily expenditure, your tracking accuracy, or how your weight fluctuates from week to week.
Product data can miss too. A page can lag behind a new label, and even labels do not always match lab measurements exactly.
Small differences in calories or macros are normal.
How to use the result
Use the number as a starting point. Then watch your weight trend, hunger, energy, and how well the plan holds up in a normal week.
If the result does not match real life, adjust the plan. The formula is here to guide you, not to argue with reality.
If a product page conflicts with the package in your hand, trust the package.
Sources
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Open Food Facts Knowledge Base. Are there conditions to use the API?
Official Open Food Facts page about reusing the database.
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Mifflin MD, et al. A new predictive equation for resting energy expenditure in healthy individuals.
Original paper for the Mifflin-St Jeor formula.
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Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review.
Review comparing common calorie formulas.
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Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight.
Explains why body weight does not change in a straight line.
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Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise.
Background for the protein ranges used by the calculator.
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Slavin JL. Position of the American Dietetic Association: health implications of dietary fiber.
Source for the 14 g per 1,000 kcal fiber rule.
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Urban LE, et al. Food Label Accuracy of Common Snack Foods.
Shows that label values can still differ from lab measurements.