Last Updated February 2026

Sources & Methodology

VERSION 1.0 · BOLEWOOD GROUP, LLC

Rubric is a health tracking and coaching application. It is not a medical device. Every number in Rubric — calorie targets, macro splits, daily scores, AI coaching responses — is either calculated from a published formula or generated as an estimate by AI. This page documents where those numbers come from.

1. Calorie Targets

Your daily calorie target is estimated using the Mifflin-St Jeor equation, the most widely validated formula for predicting Basal Metabolic Rate (BMR) in healthy adults.

For men

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5

For women

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

Your BMR is then multiplied by an activity factor based on the activity level you selected during setup to estimate your Total Daily Energy Expenditure (TDEE). Your calorie target is derived from this TDEE adjusted for your stated goal (lose fat, maintain, or build muscle).

If you have an active protocol with a calorie ceiling or target, that committed target temporarily overrides the calculated baseline for the duration of the protocol.

Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. "A new predictive equation for resting energy expenditure in healthy individuals." American Journal of Clinical Nutrition. 1990;51(2):241-247.
https://pubmed.ncbi.nlm.nih.gov/2305711/

2. Macronutrient Distribution

Macro splits (the ratio of protein, carbohydrates, and fat in your daily target) are based on ranges recommended by major health organizations. During onboarding, you select a dietary strategy — such as balanced, high protein, low carb, or keto — each of which maps to a specific macro split.

Standard caloric densities used in all calculations:

MacronutrientCalories per gram
Protein4 kcal
Carbohydrate4 kcal
Fat9 kcal
U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition. December 2020.
https://www.dietaryguidelines.gov/
World Health Organization. "Healthy Diet" Fact Sheet.
https://www.who.int/news-room/fact-sheets/detail/healthy-diet
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.
https://nap.nationalacademies.org/catalog/10490/

3. Nutritional Estimates from Meals

When you log a meal by photo or text, Rubric uses AI models to identify the food and estimate its nutritional content. These estimates are automated approximations and may be incomplete or inaccurate. They are not sourced from laboratory analysis of your specific meal.

The AI models are trained on publicly available nutritional databases, including data published by the U.S. Department of Agriculture.

You can adjust any estimate using the Universal Resolver — three dials for calories, weight, and portion size — before finalizing an entry. Rubric treats your adjustments as the final record.

U.S. Department of Agriculture, Agricultural Research Service. FoodData Central.
https://fdc.nal.usda.gov/

4. Daily Rubric Score

Your Rubric Score is a deterministic daily number ranging from 3 to 99. It is computed entirely by formula — no AI is involved in scoring.

Formula

Rubric Score = Performance Index × Adherence Multiplier × 3

Performance Index (1–11)

The average of three component indices:

Each component index maps your actual data to a 1–11 scale. The Performance Index is the average of the three.

Adherence Multiplier (1×, 2×, or 3×)

Based on two factors:

The multiplier rewards complete records and protocol commitment. It does not measure what you ate or how well you slept — only whether you logged the data and honored the protocols you set for yourself.

A note on "adherence": In Rubric, adherence refers to record completeness and protocol commitment — whether you logged your data and honored your self-defined behavioral contracts. It does not refer to dietary adherence (following a specific diet), medication adherence, or any clinical compliance metric.

Eligibility

Your score only appears when you have logged sleep data, activity data, and at least one nutrition entry for the day.

Full scoring breakdown: How the Rubric Score Works
Adherence Multiplier details

5. Protocols

Protocols are behavioral contracts you define for yourself with specific, measurable rules — such as "at least 7 hours of sleep" or "under 2,200 calories." Rubric evaluates these rules against your logged data automatically (for HealthKit-sourced metrics) or via daily attestation (for self-reported commitments).

Protocol evaluation uses a 3-day rolling window: if new health data arrives (for example, after a delayed HealthKit sync), Rubric re-evaluates the previous 72 hours. After three days, results are locked.

Protocols are limited to 3 active protocols at a time. Skip budgets allow up to 10% of a protocol's duration to be skipped without affecting your adherence record.

Protocol rules are evaluated deterministically against your data. No AI is involved in protocol evaluation.

6. AI Coaching

Rubric's AI Coach is a wellness assistant that answers questions about your logged data. It can explain your score, suggest what to eat, compare your current week to past weeks, and provide context on your health trends.

The Coach is powered by large language models. Its responses are automated suggestions for informational purposes only — not clinical recommendations, diagnoses, or treatment plans. The Coach does not have medical training and cannot replace a qualified healthcare professional.

How the Coach works

What the Coach is not

7. Health Data

All biometric data in Rubric — sleep, activity, heart rate, workouts, weight — comes from Apple HealthKit. Rubric does not collect biometric data independently.

Rubric uses Apple's native HKStatisticsQuery API for proper deduplication of data from multiple sources (Apple Watch, Peloton, Strava, etc.). This prevents double-counting when multiple devices record the same activity.

Your biometric data is stored in your secured Rubric account and is never sold, shared with advertisers, or used for purposes other than providing you with your health tracking experience.

Meal photos are processed by AI for nutrition analysis and then discarded from Rubric's servers. They are not retained.

8. What Rubric Is Not

Rubric is designed to help you track health data and build consistent habits. It is not a medical device and is not regulated as one. It does not provide:

All estimates, scores, and coaching responses are for informational purposes only. Always consult a qualified healthcare professional before making changes to your diet, exercise routine, or health regimen.

9. Questions

If you have questions about Rubric's methodology, data sources, or how a specific number was calculated, contact us at support@rubric.fit.

Last updated: February 2026