Data Sources

Every formula, reference constant, categorical range, percentile table, and food calorie entry used across the VivMetric platform is drawn exclusively from public, freely accessible publications issued by the eight authorities listed below. This page documents each source with its official reference URL and a detailed description of the specific data elements VivMetric extracts. In cases where a source document is periodically revised, the version or release identifier used by VivMetric is noted. Visitors are encouraged to open each source URL directly to verify the original publication, review full methodology, and check for any updates issued by the source authority after VivMetric's Last Updated date. Last Updated: July 2026.

Full Source Reference Table

Source Name	Reference URL	What VivMetric Uses It For
Centers for Disease Control and Prevention (CDC) Atlanta, GA, U.S. HHS	https://www.cdc.gov/healthyweight/assessing/bmi/index.html https://www.cdc.gov/growthcharts/index.htm	BMI categories for U.S. adult populations (18.5–24.9 normal, 25.0–29.9 overweight, 30.0+ obese classes I–III). CDC 2000 BMI-for-age growth chart percentiles for ages 2–19 years, split by gender: 5th, 85th, and 95th percentile thresholds used in the Teen BMI Calculator percentile reference. Division of Nutrition, Physical Activity, and Obesity (DNPAO) adult BMI screening guidance verbatim excerpts used on the BMI formula explained guide article.
World Health Organization (WHO) Geneva, Switzerland	https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight WHO Global Database on Body Mass Index technical report	International standard BMI category definitions used as the primary reference on the Adult BMI Calculator, including the WHO additional Asian population reference cutoff annotations shown as a secondary, clearly separated reference table. WHO Global Database on BMI methodology notes and country comparison framework referenced in the BMI Formula Explained guide article. WHO child growth standards (Multicentre Growth Reference Study, MGRS) baseline constants referenced for the pediatric BMI cross-reference sections.
National Institutes of Health (NIH) Bethesda, MD, U.S. HHS	Mifflin-St Jeor BMR equation validation (PubMed Central) NHLBI BMI and BMR educational materials NIH-supported National Sleep Foundation sleep duration panel	Mifflin-St Jeor basal metabolic rate formula constants used as the primary BMR output on the BMR Calculator, plus the revised Harris-Benedict (1984) equation used as the secondary, side-by-side BMR output. TDEE five-point activity factor definitions (sedentary, lightly active, moderately active, very active, extra active) drawn from NIH NHLBI obesity education guidelines. National Sleep Foundation 2015 age-group sleep duration recommendation ranges (newborn through 65+ years) used on the Sleep Duration Guide and as the reference output labels on the Sleep Cycle Calculator.
United States Department of Agriculture (USDA) Washington, D.C.	USDA FoodData Central Dietary Guidelines for Americans	Food calorie reference values (kilocalories per 100 grams) and macronutrient (protein, carbohydrate, total fat, saturated fat, dietary fiber, sugar, sodium) ranges used throughout the Food Calorie Table, organized by USDA food group taxonomy. FoodData Central Foundation Foods and SR Legacy datasets cross-referenced for the food category list. Dietary Guidelines for Americans general reference calorie ranges by age and gender reproduced as a secondary, clearly labeled reference appendix table on the Weekly Calorie Budget calculator.
National Sleep Foundation (NSF) Arlington, VA	https://www.sleepfoundation.org/sleep-tools-tips/healthy-sleep-tips NSF Sleep Duration Recommendations Consensus Paper, Sleep Health 2015	Primary sleep duration reference ranges by age group: 0–3 months, 4–11 months, 1–2 years, 3–5 years, 6–13 years, 14–17 years, 18–25 years, 26–64 years, and 65+ years, each with "recommended," "may be appropriate," and "not recommended" bands as published in the 2015 consensus paper. NSF 90-minute ultradian sleep cycle framework used as the structural basis for the Sleep Cycle Calculator forward/backward time counting algorithm, with explicit citation on the calculator output page.
Institute of Medicine (IOM / National Academy of Medicine) Washington, D.C.	Water Requirements, Impacts, and Cognition in Healthy People (IOM 2004) National Academies Press dietary reference intakes	Adequate Intake (AI) reference values for total water per day by age and gender, used as the primary benchmark reference table on the Daily Water Intake Calculator. IOM 30–35 mL per kilogram of body weight baseline water reference factor used as one of the three input-adjusted calculation methods on the water intake tool, alongside the EFSA reference and the weight-plus-activity adjustment model. Dietary Reference Intake (DRI) energy expenditure constants used for cross-check validation of the TDEE activity factor ranges.
European Food Safety Authority (EFSA) Parma, Italy	https://www.efsa.europa.eu/en/topics/topic/dietary-reference-values-water EFSA Scientific Opinion on DRV for water, EFSA Journal 2010	European DRV (Dietary Reference Values) for total water intake, used as the secondary reference table alongside the IOM values on the Daily Water Intake Calculator. EFSA 25 mL per kilogram body weight adult baseline water reference factor, displayed as a side-by-side comparison output. EFSA population reference intake (PRI) energy values, cross-referenced for the TDEE calculator secondary method validation. EFSA caffeine and hydration notes used as a clearly labeled, separate reference appendix on the Water Intake Standards guide article.
Compendium of Physical Activities Arizona State University, USDA, ACSM	https://sites.google.com/site/compendiumofphysicalactivities/ 2024 Compendium Update, Medicine & Science in Sports & Exercise	Metabolic Equivalent of Task (MET) values for all labeled activity categories on the Exercise Calorie Burn Calculator: running, walking, cycling, swimming, strength training, household activities, yard work, sports, and fitness classes. The standard 1.0 MET = 3.5 mL O₂ per kg per minute resting metabolic constant is used throughout. Calorie burn calculation formula: kcal per minute = MET × weight in kilograms / 200, is implemented verbatim per the Compendium calculation specification and cited on the Calorie Burn MET Values guide article.

How We Use Each Source: Detailed Breakdown

CDC: BMI Categories and Pediatric Growth Charts

The Centers for Disease Control and Prevention provides two core data families used across VivMetric. First, the DNPAO adult BMI screening guidelines supply the categorical thresholds displayed alongside every adult BMI result. Second, the CDC 2000 Growth Charts — specifically the BMI-for-age data sets for males and females aged 2 years 0 months through 19 years 11 months — supply the percentile framework for the Teen BMI Calculator. VivMetric interpolates month-by-month percentile boundaries linearly between published chart data points, using the identical interpolation method documented in the CDC Growth Chart training materials. The 5th, 85th, and 95th percentile markers are reproduced exactly as published, with standard CDC weight-status category labels (underweight, healthy weight, overweight, obese). All interpolated values are clearly identified as reference interpolations, not direct chart entries, on the teen calculator output page.

WHO: International BMI Standards

The World Health Organization's international BMI standard provides the default categorical labels on the Adult BMI Calculator, as the WHO classification system is the most widely referenced in global public health publications. WHO additional public health annotations for Asian populations — lower public health action cutoff points at BMI 23.0 and 27.5 — are presented in a separate, distinctly labeled reference table so that visitors can view both frameworks without conflation. The WHO Global Database on BMI methodology documentation and country-specific mean BMI summaries are cited in the BMI Formula Explained guide article to provide population context, but individual country mean values are not used to modify any individual calculator output.

NIH: BMR/TDEE Formulas and Sleep Duration

The National Institutes of Health — via the National Heart, Lung, and Blood Institute and via PubMed Central — is the source for the two BMR equations implemented on the BMR Calculator. The Mifflin-St Jeor equation, validated against direct calorimetry in 2005 and widely considered the most accurate population-level BMR predictor for adults, is presented as the primary BMR output. The 1984 revised Harris-Benedict equation is presented as the secondary output for historical comparison. The five standard TDEE activity multipliers (1.2, 1.375, 1.55, 1.725, 1.9) with their associated descriptive labels are drawn from the NIH NHLBI obesity education guidelines and cross-referenced against the original WHO/FAO/UNU joint consultation technical report series. Sleep duration age-group ranges are sourced from the National Sleep Foundation 2015 consensus panel methodology published in Sleep Health journal and supported by the NIH National Institute on Aging and National Heart, Lung, and Blood Institute.

USDA: Food Calorie Data and Dietary Guidelines

The United States Department of Agriculture FoodData Central is the exclusive source for all food calorie and macronutrient reference data in the Food Calorie Table. The current VivMetric reference dataset was extracted from FoodData Central SR Legacy and Foundation Foods releases, using generic (not branded) food entries only. Each food category on the table displays a calorie range rather than a single value to reflect the natural variability within each category (for example, different cuts of meat, different ripeness levels of fruit, different preparation methods). Preparation method modifiers (raw, boiled, baked, fried, roasted) are displayed as separate rows only where FoodData Central contains distinct entries for each method; otherwise, preparation effects are noted in footnotes. USDA Dietary Guidelines for Americans general calorie reference ranges by age and gender are reproduced as a separate appendix on the Weekly/Monthly Calorie Budget calculator.

NSF, IOM, EFSA: Hydration and Sleep Framework

The National Sleep Foundation, the Institute of Medicine (now the National Academy of Medicine), and the European Food Safety Authority collectively provide the hydration and sleep reference framework across the Daily Water Intake Calculator, Sleep Cycle Calculator, and Sleep Duration Guide. The NSF 2015 sleep duration consensus provides the nine-category age-group range table used across all sleep pages. The IOM 2004 report on water requirements provides the U.S.-reference adequate intake table and the 30–35 mL/kg baseline weight factor used on the water calculator. The EFSA 2010 DRV for water provides the European-reference adequate intake table and the 25 mL/kg baseline factor used as a side-by-side comparison. These three frameworks are presented as distinctly labeled parallel references on every hydration and sleep output so that the visitor can choose the regional framework most relevant to their context.

Compendium of Physical Activities: MET Values

The Compendium of Physical Activities is the authoritative source for MET (Metabolic Equivalent of Task) values in the Exercise Calorie Burn Calculator. The 2024 Compendium update published in Medicine & Science in Sports & Exercise provides the current reference values used across all activity categories on the tool. Each MET value represents the ratio of a specific activity's metabolic rate to the standard resting metabolic rate (3.5 mL of oxygen per kilogram of body weight per minute, equivalent to approximately 1 kcal per kg per hour in standard convention). The Compendium activity coding system is used verbatim for the activity category naming structure on the calculator, and the calorie burn formula (kcal = MET × kg × minutes / 200) is implemented exactly per the Compendium technical specification with no modification.

Frequently Asked Questions

Last Updated: July 2026