PERSONALNUTRIAPP - CALCULATION RATIONALE FOR DIET PLANS

Purpose

This document presents the formulas used in the Artificial Intelligence instructions for the development of diet protocols.

The purpose is to provide clarity regarding the scientific basis of the calculations employed to estimate energy expenditure, the distribution of macronutrients, and individualized dietary adequacy.

Below are the main equations, as well as the most relevant scientific references that validate them.

1) Basal Metabolic Rate (BMR)

BMR corresponds to the minimum energy expenditure required to maintain vital functions at rest.

Mifflin–St Jeor Equation (1990)

• Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
• Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161

Considered the most accurate currently for healthy adults.

• Harris–Benedict Equation (1918, revised in 1984)
• Men: BMR = 88.36 + (13.4 × weight kg) + (4.8 × height cm) − (5.7 × age)

Women: BMR = 447.6 + (9.2 × weight kg) + (3.1 × height cm) − (4.3 × age)

A classic equation, still used in clinical and research contexts.

2) Physical Activity Factor (PAF)

To obtain the Total Energy Expenditure (TEE), BMR is multiplied by the activity factor:

1. Sedentary: × 1.2
2. Lightly active: × 1.375
3. Moderately active: × 1.55
4. Very active: × 1.725
5. Extremely active: × 1.9

3) Macronutrient Distribution

After calculating TEE, calories are distributed among macronutrients according to scientific recommendations:

• Carbohydrates: 45–65% of total calories
• Proteins: 10–35% of total calories (equivalent to 1.2–2.0 g/kg/day)
• Fats: 20–35% of total calories

The distribution is adjusted according to the goal: maintenance, weight loss, muscle definition, or hypertrophy.

4) Important Considerations

The equations are estimates and may present a margin of error.

The gold standard for measuring energy expenditure is indirect calorimetry.

Individual adjustments are required for specific populations (elderly, obese, athletes, clinical conditions).

Scientific References

1. 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.
2. Harris JA, Benedict FG. - A Biometric Study of Basal Metabolism in Man. Carnegie Institute of Washington, 1919.
3. Compher C, Frankenfield D, Keim N, Roth-Yousey L. - Best Practice Methods to Apply to Measurement of Resting Metabolic Rate in Adults: A Systematic Review. J Am Diet Assoc. 2006;106(6):881-903.
4. Weijs PJM. - Validity of predictive equations for resting energy expenditure in US and Dutch adults. Clin Nutr. 2008;27(2):150-157.
5. Frankenfield D, Roth-Yousey L, Compher C. - Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Non-Obese and Obese Adults: A Systematic Review. J Am Diet Assoc. 2005;105(5):775-789.