This page lists the scientific sources and formulas behind the calculations and recommendations in the Mira app: daily calorie targets, macronutrients, water, fiber, and Body Mass Index (BMI), as well as where the food data itself comes from. We rely on widely accepted, peer-reviewed methods and guidance from international health organizations.
1. Basal Metabolic Rate (BMR)
BMR is the energy your body uses at rest. We compute it with the Mifflin-St Jeor equation, one of the most accurate formulas for healthy adults:
Source: Mifflin MD, St Jeor ST, et al. "A new predictive equation for resting energy expenditure in healthy individuals." Am J Clin Nutr. 1990;51(2):241–247. pubmed.ncbi.nlm.nih.gov/2305711
2. Total Daily Energy Expenditure (TDEE)
Total daily expenditure is BMR multiplied by a physical activity level (PAL) factor. The level describes everyday life only: work, walking around, chores. Workouts are not part of it: they are logged separately (see section 3).
| Activity level | Factor |
|---|---|
| Sedentary (mostly sitting) | × 1.2 |
| Light (some walking or standing) | × 1.375 |
| Moderate (on your feet most of the day) | × 1.55 |
| Active (physical work) | × 1.725 |
| Very active (hard physical labour) | × 1.9 |
Source: physical activity level (PAL) factors per FAO/WHO/UNU. Human energy requirements. 2004. fao.org/3/y5686e
3. Workout Calories
A logged workout adds only the energy spent above rest. MET values count the whole burn including the resting one (1 MET), which your BMR already covers, so we subtract it and scale by your own resting rate instead of the generic 1 kcal/kg/h:
Everyday activities (studying, office work, chores) are not workouts: they are part of your activity level, so they are not logged again.
Sources: Herrmann SD, et al. "2024 Adult Compendium of Physical Activities." J Sport Health Sci. 2024;13(1):6–12. pubmed.ncbi.nlm.nih.gov/38242596 · Corrected METs, pacompendium.com/corrected-mets
4. Calorie Target & Safe Pace
For weight loss or gain we adjust TDEE by a calorie deficit or surplus, based on the energy density of body mass, roughly 7700 kcal per kg:
To keep recommendations safe, we apply guards:
- rate of weight change no more than ~1% of body weight per week;
- daily deficit/surplus no more than 25% of TDEE;
- minimum intake never below 1500 kcal (male) / 1200 kcal (female) without medical supervision.
Sources: Wishnofsky M. "Caloric equivalents of gained or lost weight." Am J Clin Nutr. 1958. pubmed.ncbi.nlm.nih.gov/13594881 · CDC, "Losing Weight: safe rate ~0.5–1 kg/week". cdc.gov/healthyweight · minimum-intake floors per NIH / Academy of Nutrition and Dietetics guidance.
5. Macronutrients (protein, fat, carbs)
We split the calorie target across macros using their energy values (Atwater factors). The split percentages depend on the chosen diet type and stay within the Acceptable Macronutrient Distribution Ranges (AMDR):
| Macronutrient | Energy | Range (AMDR) |
|---|---|---|
| Protein | 4 kcal/g | 10–35% |
| Carbs | 4 kcal/g | 45–65% |
| Fat | 9 kcal/g | 20–35% |
For example, the "Balanced" type is 25% protein / 50% carbs / 25% fat. Keto is an intentional therapeutic exception with high fat.
Sources: Atwater energy factors: FAO, "Food energy: methods of analysis and conversion factors." fao.org/4/y5022e · AMDR ranges: Institute of Medicine (IOM), Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. 2005. nap.nationalacademies.org/catalog/10490
6. Fiber
We compute the fiber target in proportion to calories:
Source: Institute of Medicine (IOM), Dietary Reference Intakes, 2005 (~14 g fiber per 1000 kcal). nap.nationalacademies.org/catalog/10490
7. Water Target
We derive the daily water target from body weight, adjusted for activity level:
| Activity level | Factor |
|---|---|
| Sedentary | 1.0 |
| Light | 1.1 |
| Moderate | 1.2 |
| Active | 1.3 |
| Very active | 1.5 |
Sources: clinical guidance of ~30–35 ml/kg of body weight · European Food Safety Authority (EFSA), "Scientific Opinion on Dietary Reference Values for water." EFSA Journal. 2010;8(3):1459. efsa.europa.eu/en/efsajournal/pub/1459
8. Body Mass Index (BMI)
We compute BMI with the standard formula and classify it using the World Health Organization (WHO) categories:
| BMI | Category |
|---|---|
| < 16.0 | Severe thinness |
| 16.0 – 17.0 | Moderate thinness |
| 17.0 – 18.5 | Mild thinness |
| 18.5 – 25.0 | Normal |
| 25.0 – 30.0 | Overweight |
| 30.0 – 35.0 | Obese class I |
| 35.0 – 40.0 | Obese class II |
| ≥ 40.0 | Obese class III |
Source: World Health Organization (WHO), BMI classification. who.int: Body mass index
9. Meal Calorie Distribution
The recommended split of daily calories across meals depends on the goal. For weight loss we shift more calories to earlier in the day (larger breakfast, smaller dinner), supported by research:
| Goal | Breakfast | Lunch | Dinner | Snack |
|---|---|---|---|---|
| Weight loss | 35% | 30% | 20% | 15% |
| Maintain | 25% | 30% | 25% | 20% |
| Weight gain | 25% | 25% | 25% | 25% |
Source: Jakubowicz D, et al. "High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women." Obesity (Silver Spring). 2013;21(12):2504–2512. pubmed.ncbi.nlm.nih.gov/23512957
10. Food Data
Mira's food catalogue is compiled from open sources: publicly available food datasets and manufacturer information published openly (ingredients and nutrition from the label). We do not buy or use closed or licensed databases belonging to other apps.
- rows without real nutrition values are rejected rather than filled in with guesses;
- every row keeps a record of where it came from, and a link back to the original where one exists;
- the data can be incomplete or out of date, because manufacturers reformulate. Check the product label where it matters.
Foods you create yourself (including from photo recognition) belong to your account only and are not added to the shared catalogue.
11. Updates
We revise these methods as new scientific evidence emerges. If you have questions about the calculations, contact us: support@mira-fit.com.
Questions about this document? Write to us at support@mira-fit.com.