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Methodology & Sources

How Nutra estimates BMR, TDEE, calorie targets, macronutrient splits, and water intake. These are general wellness estimates, not medical advice.

These are general wellness estimates intended for informational and educational purposes only and are not medical advice. Always consult a qualified professional for personalized guidance.

TABLE OF CONTENTS

  1. Basal Metabolic Rate (BMR)
  2. Total Daily Energy Expenditure (TDEE)
  3. Calorie Targets by Goal
  4. Macronutrient Splits
  5. Daily Water Intake
  6. References

Basal Metabolic Rate (BMR)

Nutra estimates BMR using the Mifflin–St Jeor equation [1], based on weight, height, age, and sex.

Reference: [1].

Formulas (metric units):

  • Male: 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + 5
  • Female: 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) − 161
Example calculation

Example (male, 75 kg, 180 cm, 30 years): 10×75 + 6.25×180 − 5×30 + 5 = 1730 kcal/day (approx.).

Total Daily Energy Expenditure (TDEE)

TDEE is estimated by multiplying BMR by a physical activity level (PAL) factor [2] selected to reflect typical daily activity.

Context on PAL and energy needs: [2].

Activity multipliers:

  • Sedentary: 1.50
  • Lightly Active: 1.75
  • Moderately Active: 2.00
  • Very Active: 2.20
  • Athlete: 2.30
Example calculation

Using the BMR example (1730 kcal) with Moderately Active (2.00): TDEE ≈ 1730 × 2.00 = 3460 kcal/day.

Calorie Targets by Goal

Targets start from TDEE, then apply an adjustment. We use commonly adopted heuristics (e.g., ~20% deficit for weight loss, ~15% surplus for weight gain) [3]. These are general-purpose targets and may not fit individual needs.

Related guidance on safe weekly weight change (approx. 500–1000 kcal/day deficit): [3].

Goal adjustments (applied to TDEE):

  • Weight loss: 0.80 × TDEE (about 20% deficit)
  • Maintain: 1.00 × TDEE
  • Weight gain: 1.15 × TDEE (about 15% surplus)
Example calculation

Using TDEE ≈ 2682 kcal: weight loss ≈ 2146 kcal/day; weight gain ≈ 3084 kcal/day.

Macronutrient Splits

Preset macro templates are general templates (not prescriptions). Balanced aligns with AMDR ranges [4]. Low-carb definitions vary in the literature; our preset below is a user-selected style that reduces carbohydrate below the AMDR lower bound. Ketogenic diets typically use 5–10% carbs with higher fat [7]. Higher-carbohydrate patterns are often used in endurance contexts and remain within AMDR [8].

References: [4], [7], [8].

Preset macro templates (of calories):

  • Balanced: protein 30%, fat 25%, carbs 45% (AMDR-aligned)
  • Low-carb: protein 30%, fat 50%, carbs 20% (user-selected style; below AMDR lower bound [4])
  • High-protein: protein 35%, fat 20%, carbs 45% (protein capped at 35% per AMDR [4])
  • Keto: protein 20%, fat 70%, carbs 10% (user-selected; may fall outside AMDR [7])
  • High-carb: protein 15%, fat 25%, carbs 60% (AMDR-aligned; endurance context [8])
Example calculation

Using weight-loss target ≈ 2146 kcal with Balanced template:

  • Protein: ~161 g/day
  • Fat: ~60 g/day
  • Carbs: ~241 g/day

Daily Water Intake

Baseline estimate uses ~30 mL/kg, plus small adjustments for activity and goals [5][6]. Individual needs vary widely.

References: [5], [6].

Baseline and adjustments:

  • Baseline: 30 mL/kg of body mass
  • Activity adders (approximate):
  • Sedentary: +0 mL
  • Lightly Active: +400 mL
  • Moderately Active: +600 mL
  • Very Active: +850 mL
  • Athlete: +1200 mL
  • Goal adders (approximate):
  • Weight loss: +500 mL
  • Weight gain: +200 mL
  • Maintain: +0 mL
Example calculation

Example (75 kg, Moderately Active, weight loss): 30×75 = 2250 mL, +600 mL, +500 mL ≈ 3350 mL → ~3.4 L/day.

References

  1. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990. DOI • PubMed
  2. FAO/WHO/UNU Expert Consultation. Human energy requirements. 2001. Overview • PDF
  3. U.S. CDC. Healthy Weight: Losing Weight. CDC
  4. Institute of Medicine (US). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Protein. 2002/2005. (AMDR) NCBI Bookshelf
  5. National Academies. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. 2005. NAP
  6. American College of Sports Medicine (ACSM). Exercise and Fluid Replacement. Med Sci Sports Exerc. 2007. DOI • PubMed
  7. Paoli A. Ketogenic diet for obesity: friend or foe? Int J Environ Res Public Health. 2014. Publisher • PubMed
  8. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet. 2016. PubMed

Last updated: 2025-11-06

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