FluidMacros

How we estimate

Last updated: October 24, 2026

FluidMacros helps you plan and track what you eat. Every number in the App is an estimate — here is how we make them, and where they can be off.

Foods you type and recipes

We read each ingredient line ("2 eggs", "1 cup cooked rice"), convert the amount to grams using standard household measures and typical portion sizes, and multiply by per-100-gram nutrition values from USDA FoodData Central. Foods not in our built-in table are looked up in USDA’s database; if there is no confident match, we tell you instead of guessing.

When you log food, we assume grains, pasta, and beans are cooked and meat is weighed cooked, unless you say otherwise — you can switch any of these between cooked and dry/raw. Amounts we had to guess are marked so you can adjust them.

On a test set of 25 published recipes, about half of our estimates land within 15% of the recipe author’s own numbers and three in four within 30% (the authors’ numbers are estimates too). Brand-specific products, restaurant dishes, and vague amounts ("a drizzle", "a handful") are the biggest sources of error.

Recipe swaps

Swap suggestions recalculate the recipe with the new ingredient’s nutrition. Results depend on the brands you buy and how you cook — check labels if exact numbers matter. Imported recipes are a copy from the source website at the time you imported them; the original may have changed since.

Allergens

Allergen filters only hide items whose source lists the allergen. About half of restaurant menu items list no allergens, and no source accounts for cross-contact. If you have a food allergy, always confirm with restaurant staff, the current menu, or the package label before ordering or eating.

Restaurants

Restaurant menu nutrition comes from each chain’s published nutrition information, or — where marked “self-reported by the restaurant” — from the restaurant itself, which we review for completeness but do not independently verify. Menus change and portions vary by location, so numbers may be out of date — tap the flag next to an item to tell us. Always confirm allergens with the restaurant.

Barcodes

Scanned products come from Open Food Facts, a free database built by volunteers from product labels. Entries can be incomplete or out of date; check the label on the package.

Your targets

Your daily calorie and macro targets are the numbers you set (or that we suggest from your choices during setup). They are general guidance, not a medical prescription.

Not medical advice

FluidMacros is not a medical device and does not diagnose, treat, or manage any condition. If you are pregnant, are managing a health condition such as diabetes or kidney disease, or have a history of disordered eating, talk to a doctor or registered dietitian before changing how you eat.

Data sources and credits