Basal Metabolic Rate (BMR)

The app utilises the Mifflin-St Jeor equation as the foundational baseline for all nutritional calculations. By inputting the user's sex, age, weight, and height, the formula estimates the number of calories the body requires to maintain vital functions while at rest. We selected this specific equation because it is recognised in clinical nutrition as the most accurate predictive tool for the modern adult population.

 

Formula:

Male BMR: 10 * weight_kg + 6.25 * height_cm - 5 * age_years + 5

Female BMR: 10 * weight_kg + 6.25 * height_cm - 5 * age_years - 161

 

Source: Mifflin, M. D., St Jeor, S. T., Hill, L. A., Scott, B. J., Daugherty, S. A., & Koh, Y. O. (1990). "A new predictive equation for resting energy expenditure in healthy individuals." The American Journal of Clinical Nutrition.

 

Total Daily Energy Expenditure (TDEE)

To account for the energy burned during daily movement and exercise, the app applies a Physical Activity Level (PAL) multiplier to the user's BMR. This allows the app to provide a "Maintenance" calorie target tailored to the user's specific lifestyle, whether they are sedentary or extremely active. This multiplier is essential to ensure the app does not under-fuel users with high physical demands.

 

Formula:

Maintenance Calories: BMR * PAL_Multiplier

 

Source: Dietary Reference Intakes for Energy, Carbohydrate, Fibre, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. (2005). National Academies Press / Academy of Nutrition and Dietetics Evidence Analysis Library.

 

Muscle-Sparing Protein Targets

Protein requirements are calculated based on a fixed multiple of the user's total body weight. The app prioritises higher protein intakes during fat-loss phases—up to 2.4 g/kg—to prevent lean muscle loss while in a calorie deficit. This weight-based approach is more effective for athletes and bodybuilders than using a simple percentage of total calories.

 

Formula:

Protein (grams): body_weight_kg * protein_multiplier

 

Source: Helms, E. R., Zinn, C., Rowlands, D. S., & Brown, S. R. (2014). "A systematic review of dietary protein during caloric restriction in resistance-trained lean athletes." International Journal of Sport Nutrition and Exercise Metabolism.

 

Performance-Driven Macronutrient Splits

Once protein needs are met, the app distributes the remaining calories between carbohydrates and fats using a percentage-based split that shifts depending on the user's goal. For "Bulk" phases, the app increases the carbohydrate ratio to 75% of remaining calories to maximise glycogen storage and training intensity. This ensures that users have the fuel necessary for high-performance training while maintaining healthy fat thresholds.

 

Formula:

Remaining Calories: goal_calories - (protein_grams * 4) Carbohydrates (grams): (carb_split_percentage * remaining_calories) / 4 Fat (grams): (fat_split_percentage * remaining_calories) / 9

 

Source: Lambert, C. P., Frank, L. L., & Evans, W. J. (2004). "Macronutrient considerations for the sport of bodybuilding." Sports Medicine.