The science behind the app
Tracking what you eat is only worth anything if the numbers behind it hold up. Every formula Cal 3D uses — your calorie target, the macro split, the micronutrient limits — is listed here with its published source and with the file in the app that implements it.
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This is not medical advice
Cal 3D is not a medical device. It makes no diagnoses, treats no conditions and does not replace advice from a doctor or dietitian. Talk to a medical professional before changing your diet — especially with diabetes, kidney or liver disease, during pregnancy or breastfeeding, and with food allergies. The full health notice is part of the terms of use.
Calorie target and pace
These are the sources behind the daily target the app shows you at the end of setup.
Resting metabolic rate. Cal 3D uses Mifflin-St Jeor: 10 × kg + 6.25 × cm − 5 × years, plus 5 for men and minus 161 for women. If you give no sex, you get the midpoint of both terms (−78).
Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241–247.
pubmed.ncbi.nlm.nih.govIn the app:
nutritionGoals.ts:9–17From resting rate to daily burn. The three activity bands multiply by 1.3, 1.55 and 1.725 — the standard PAL bands for little, moderate and heavy movement.
FAO/WHO/UNU. Human Energy Requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. FAO Food and Nutrition Technical Report Series 1. Rome; 2004.
fao.orgIn the app:
plan.ts:39–78How fast a goal can be reached. One kilogram of body mass is planned at 7,700 kcal, which is where the daily surplus or deficit for your chosen pace comes from.
Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr. 1958;6(5):542–546.
pubmed.ncbi.nlm.nih.govIn the app:
plan.ts:39–78Floors. The target never drops below 1,200 kcal, and never below 1,500 for men — whatever weight and pace would work out to arithmetically.
National Institutes of Health, National Heart, Lung, and Blood Institute. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. NIH Publication 98-4083; 1998.
nhlbi.nih.gov (PDF)In the app:
plan.ts:39–78
Protein, fat and carbohydrate
These are the sources behind how the daily target is split across the three macros.
How much protein. 1.6 to 2.2 grams per kilogram of bodyweight depending on your goal — at the upper end in a deficit, because that is where lean mass needs protecting.
Aragon AA, Schoenfeld BJ, Wildman R, Kleiner S, VanDusseldorp T, Taylor L, et al. International Society of Sports Nutrition position stand: diets and body composition. J Int Soc Sports Nutr. 2017;14:16.
pubmed.ncbi.nlm.nih.govIn the app:
nutritionGoals.ts:9–17The ranges within which a split makes sense at all (AMDR). Fat defaults to 25 % of energy and carbohydrate takes the remainder.
Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005.
nap.nationalacademies.orgIn the app:
nutritionGoals.ts:9–17The conversion between grams and kilocalories: 4 for protein, 4 for carbohydrate, 9 for fat. Cal 3D also uses it to check every recognised meal for nutrition values that contradict each other.
FAO. Food Energy — Methods of Analysis and Conversion Factors. FAO Food and Nutrition Paper 77. Rome; 2003.
fao.orgIn the app:
aiScan.ts:362–364
Fibre, sugar and salt
These are the sources behind the three values that run alongside the macros.
Fibre. 14 grams per 1,000 kilocalories, plus the adequate intake by age and sex during setup (38 g for men up to 50, 25 g for women up to 50).
Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005.
nap.nationalacademies.orgIn the app:
plan.ts:106–120Added sugar. At most 10 % of daily energy.
World Health Organization. Guideline: Sugars Intake for Adults and Children. Geneva; 2015.
who.intIn the app:
nutritionGoals.ts:9–17Sodium. 2,300 milligrams a day as an upper limit, the same for everyone.
U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020–2025. 9th ed.; December 2020.
odphp.health.govIn the app:
plan.ts:39–78
Recognition and nutrition data
These are the sources behind what Cal 3D recognises on the plate — and behind the nutrition values it looks up for it.
The benchmark a photo estimate has to be measured against. 28 weighed plates, 29.9 % MAPE on kilocalories — and the finding that the error has a direction: large portions read low, small ones high. These numbers describe the inherited photo pipeline, not Cal 3D itself.
Thames Q, Karpur A, Norlund W, Xia Q, Panait L, Weyand T, Sim J. Nutrition5k: Towards Automatic Nutritional Understanding of Generic Food. CVPR 2021:8903–8911.
openaccess.thecvf.comIn the app:
measuredPortion.ts:5–12The built-in food database: around 8,600 generic entries, almost a third of them carrying a density in grams per millilitre — the exact column that turns a measured volume into a weight.
U.S. Department of Agriculture, Agricultural Research Service. FoodData Central. fdc.nal.usda.gov.
fdc.nal.usda.govIn the app:
foodDb.ts:1–40Packaged food. Barcodes and branded products are looked up there — for something with a printed nutrition table, measuring is the detour.
Open Food Facts. An open, community-maintained database of food products from around the world. The database is licensed under the Open Database License (ODbL); its individual contents are under the Database Contents License (DbCL).
world.openfoodfacts.orgLicence: ODbL 1.0, DbCL 1.0In the app:
foodDb.ts:1–40
How the measurement itself works — volume, density, grams — is set out on the method page.