The science behind the app
Tracking what you eat is only useful if the numbers behind it rest on published research. Cal Clark's calorie budget, nutrition targets, weekly pace, and macro splits follow the sources below. We will keep this page current as the app changes.
Last updated October 2026
Registration and App Setup
These are the sources we reference when we set a first calorie budget and nutrition targets during setup.
Physiology | Body Mass Index
Zierle-Ghosh A, Jan A. Physiology, Body Mass Index [Internet]. National Library of Medicine. StatPearls Publishing; 2023.
Adult Weight Management Recommendations Summary: Assess Energy Needs
Adult Weight Management Recommendations Summary - Assess Energy Needs 2014. www.andeal.org.
The Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report
The Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. National Institutes of Health; National Heart, Lung and Blood Institute; 1998.
2020 - 2025 Dietary Guidelines for Americans
2020 Dietary Guidelines | Dietary Guidelines for Americans [Internet]. Dietaryguidelines.gov. 2020.
International Society of Sports Nutrition Position Stand: Diets and Body Composition
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. Journal of the International Society of Sports Nutrition. 2017 Jun 14;14(1).
Weight loss and gain pace
These are the sources we use when we judge whether a weekly lose or gain pace matches typical published guidance. Typical loss is about 0.25 to 0.9 kg per week, about 1 to 2 lb, with a common first checkpoint of about 10% of current weight in 6 months. Typical gain is a modest surplus, about 0.25 to 0.5 kg per week. A target BMI under 18.5 is not treated as a usual healthy range. Daily calories stay within a floor and a cap. Faster rates stay available; we do not call them typical.
The Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report
The Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. National Institutes of Health; National Heart, Lung and Blood Institute; 1998.
International Society of Sports Nutrition Position Stand: Diets and Body Composition
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. Journal of the International Society of Sports Nutrition. 2017 Jun 14;14(1).
Physiology | Body Mass Index
Zierle-Ghosh A, Jan A. Physiology, Body Mass Index [Internet]. National Library of Medicine. StatPearls Publishing; 2023.
2020 - 2025 Dietary Guidelines for Americans
2020 Dietary Guidelines | Dietary Guidelines for Americans [Internet]. Dietaryguidelines.gov. 2020.
Daily calorie budget
These are the sources we reference when we estimate basal metabolic rate and activity for the daily calorie budget.
A new predictive equation for resting energy expenditure in healthy individuals
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.
2011 Compendium of Physical Activities: a second update of codes and MET values
Ainsworth BE, Haskell WL, Herrmann SD, Meckes N, Bassett DR Jr, Tudor-Locke C, et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Med Sci Sports Exerc. 2011;43(8):1575-1581.
Micronutrient Targets
These are the sources we reference when we set micronutrient targets in the app.
Daily Values
Daily Values. Nih.gov. Published 2026. Accessed July 8, 2026.
Daily Value on the Nutrition and Supplement Facts Labels
FDA. Daily Value on the Nutrition and Supplement Facts Labels. FDA. Published online March 5, 2024. Accessed July 8, 2026.
Daily Goals Macronutrient Splits
These are the sources we reference when we set daily carbohydrate, protein, and fat splits.
Dietary Guidelines for Americans 2020-2025
United States Department of Agriculture. Dietary Guidelines for Americans 2020-2025. USDA; 2020. Accessed July 6, 2026.
Description of the Acceptable Macronutrient Distribution Range
Description of the Acceptable Macronutrient Distribution Range. Nih.gov. Published November 12, 2024. Accessed July 6, 2026.
Evaluation of the Effect of Macronutrients Combination on Blood Sugar Levels in Healthy Individuals
Basturk B, Koc Ozerson Z, Yuksel A. Evaluation of the effect of macronutrients combination on blood sugar levels in healthy individuals. Iran J Public Health. 2021;50(2):280-287.
International Society of Sports Nutrition Position Stand: Diets and Body Composition
Aragon AA, Schoenfeld BJ, Wildman R, et al. International society of sports nutrition position stand: diets and body composition. Journal of the International Society of Sports Nutrition. 2017;14(1).
ISSN Exercise & Sports Nutrition Review Update: Research & Recommendations
Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: research & recommendations. Journal of the International Society of Sports Nutrition. 2018;15(1).
Defining "Low-Carb" in the Scientific Literature: A Scoping Review of Clinical Studies
Chacón V, Cara KC, Chung M, Wallace TC. Defining "low-carb" in the scientific literature: A scoping review of clinical studies. Critical Reviews in Food Science and Nutrition. 2024;65(10):1-10.
Ketogenic Diets for Body Weight Loss: A Comparison with Other Diets
Dyńka D, Rodzeń Ł, Rodzeń M, et al. Ketogenic Diets for Body Weight Loss: A Comparison with Other Diets. Nutrients. 2025;17(6):965.
Food data sources
Some of the calorie and nutrient values in Cal Clark come from the public databases below. We list the licence next to each source. We translated food names and adapted some values.
USDA FoodData Central
U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, 2019. Public domain (CC0 1.0). Food names translated by Cal Clark.
Bundeslebensmittelschlüssel (BLS) 4.0 - German Nutrient Database
Max Rubner-Institut (2025). Bundeslebensmittelschlüssel (BLS), Version 4.0. Licensed under CC BY 4.0. Contains data from BLS 4.0; food names translated and values adapted by Cal Clark. Cal Clark is not affiliated with or endorsed by the Max Rubner-Institut.
Open Food Facts
Product data from Open Food Facts, © Open Food Facts contributors, available under the Open Database License (ODbL) 1.0. Individual entries under the Database Contents License (DbCL) 1.0. Product photos under CC BY-SA 3.0.
Questions or Feedback
If you have a question about a recommendation, or you want to suggest another source, write to us: support@calclark.app