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🥗 Nutrition Planning

Macro Calculator

Get your personalized daily protein, carbohydrate, and fat targets based on your age, gender, weight, height, activity level, and fitness goal. Based on the Mifflin-St Jeor formula and ACSM guidelines.

Select your biological sex
Your current age
Your height measurement
Your current body weight
Your typical weekly physical activity
Your primary health or fitness objective

Understanding Macronutrients & Daily Targets

What Are Macronutrients?

Macronutrients are the nutrients your body needs in large amounts: protein, carbohydrates, and fats. They provide energy (calories) and are essential for growth, metabolism, and overall health. Each macronutrient has a specific role in the body:

  • Protein: Builds and repairs tissues, produces enzymes and hormones, supports immune function. 1g = 4 calories.
  • Carbohydrates: Primary energy source for the brain and muscles during exercise. 1g = 4 calories.
  • Fats: Supports cell growth, hormone production, and nutrient absorption. 1g = 9 calories.

How Your Macros Are Calculated

This calculator uses the following evidence-based approach:

  1. BMR (Mifflin-St Jeor): The most accurate predictive equation for resting energy expenditure.
  2. TDEE: BMR × Activity Factor — your total daily calorie burn.
  3. Goal Adjustment: Calories are adjusted based on your goal (maintain, lose, or gain).
  4. Macro Distribution: Based on scientific guidelines for protein (1.6-2.2g per kg), fat (20-35%), and carbs (remainder).

Protein Recommendations

Protein is essential for muscle repair, immune function, and enzyme production. Recommended daily protein intake:

  • General health: 0.8g per kg of body weight
  • Muscle building: 1.6–2.2g per kg of body weight
  • Fat loss (preserving muscle): 1.6–2.4g per kg of body weight
  • Endurance athletes: 1.2–1.6g per kg of body weight

The Academy of Nutrition and Dietetics recommends that athletes consume 1.2–2.0g per kg of body weight, depending on the type and intensity of training.

Carbohydrate & Fat Recommendations

According to the Dietary Guidelines for Americans and ACSM:

  • Carbohydrates: 45–65% of daily calories. For athletes, higher intakes (55–65%) may be needed to fuel performance.
  • Fat: 20–35% of daily calories. For optimal health, prioritize unsaturated fats (olive oil, avocados, nuts, fish).
  • Fiber: At least 25-38g per day from whole grains, vegetables, and fruits.

The Mifflin-St Jeor Formula

The Mifflin-St Jeor formula (1990) is currently considered the most accurate predictive equation for estimating Basal Metabolic Rate (BMR). It was validated against indirect calorimetry and has a lower standard deviation than older formulas like Harris-Benedict.

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

Activity Factors for TDEE

Total Daily Energy Expenditure (TDEE) is calculated by multiplying BMR by an activity factor:

  • Sedentary (1.2): Little or no exercise
  • Lightly Active (1.375): Light exercise 1–3 days/week
  • Moderately Active (1.55): Moderate exercise 3–5 days/week
  • Very Active (1.725): Hard exercise 6–7 days/week
  • Super Active (1.9): Athlete or physically demanding job

Goal Adjustments

Based on your fitness goal, daily calories are adjusted:

  • Maintain: TDEE calories (no adjustment)
  • Lose (Moderate): TDEE − 300 calories (approx. 0.5–0.7 kg loss per week)
  • Lose (Aggressive): TDEE − 500 calories (approx. 1 kg loss per week, more challenging)
  • Gain: TDEE + 300 calories (slow, quality muscle gain)

Practical Tips for Hitting Your Macros

  • Protein: Include a source of protein at every meal (meat, fish, eggs, dairy, legumes, tofu).
  • Carbs: Choose complex carbohydrates (whole grains, vegetables, fruits) over refined carbs.
  • Fats: Prioritize unsaturated fats (olive oil, avocados, nuts, seeds, fatty fish).
  • Track intake: Use a food tracking app (e.g., MyFitnessPal, Cronometer) to log meals.
  • Adjust gradually: Make small changes to your diet over time for sustainable results.

💡 Pro Tip: Studies show that consuming 1.6–2.2g of protein per kg of body weight per day is optimal for muscle growth when combined with resistance training. For a 75kg person, that's 120–165g of protein daily — approximately 30–40g per meal spread across 4 meals.

References & Further Reading

  • Mifflin, M.D., St Jeor, S.T., Hill, L.A., et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 51(2), 241-247.
  • Academy of Nutrition and Dietetics, Dietitians of Canada, & American College of Sports Medicine. (2016). Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, 48(3), 543-568.
  • American College of Sports Medicine. (2021). ACSM's Guidelines for Exercise Testing and Prescription. 11th Edition.
  • U.S. Department of Agriculture. (2020). Dietary Guidelines for Americans, 2020-2025.
  • Phillips, S.M. & Van Loon, L.J.C. (2011). Dietary protein for athletes: From requirements to optimum adaptation. Journal of Sports Sciences, 29(sup1), S29-S38.

Frequently Asked Questions

Macronutrients are the nutrients your body needs in large amounts: protein, carbohydrates, and fats. They provide energy (calories) and are essential for growth, metabolism, and overall health. Each macronutrient has a specific role in the body:

  • Protein: 4 calories per gram — builds and repairs tissues, enzymes, hormones
  • Carbohydrates: 4 calories per gram — primary energy source
  • Fats: 9 calories per gram — cell structure, hormone production, nutrient absorption

Daily macros are calculated using your Total Daily Energy Expenditure (TDEE) and your fitness goal:

  • First, your BMR is calculated using the Mifflin-St Jeor formula
  • Then TDEE = BMR × Activity Factor
  • Calories are adjusted based on your goal (maintain, lose, or gain)
  • Macros are distributed: Protein (1.6–2.2g per kg), Fat (20–35%), Carbs (remaining calories)

The Mifflin-St Jeor formula is a widely used equation to estimate Basal Metabolic Rate (BMR):

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

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

It is considered one of the most accurate BMR formulas, validated against indirect calorimetry.

Protein requirements vary based on activity level and goals:

  • General health: 0.8g per kg body weight
  • Muscle building: 1.6–2.2g per kg body weight
  • Fat loss: 1.6–2.4g per kg body weight (to preserve muscle)
  • Endurance athletes: 1.2–1.6g per kg body weight

The Academy of Nutrition and Dietetics recommends 1.2–2.0g per kg for athletes.

According to the Dietary Guidelines for Americans and ACSM:

  • Carbohydrates: 45–65% of daily calories (55–65% for athletes)
  • Fat: 20–35% of daily calories
  • Fiber: At least 25–38g per day

Prioritize complex carbohydrates (whole grains, vegetables, fruits) and unsaturated fats (olive oil, avocados, nuts, fish).

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic life functions (breathing, circulation, temperature regulation).

TDEE (Total Daily Energy Expenditure) is the total number of calories you burn in a day including all activities, exercise, and digestion.

TDEE = BMR × Activity Factor. TDEE is what you use to set your calorie targets for weight management.

Results vary based on consistency and individual factors:

  • Weight loss: 0.5–1 kg per week is sustainable (300–500 calorie deficit per day)
  • Muscle gain: 0.25–0.5 kg per month is realistic for natural lifters
  • Body composition changes: Noticeable changes typically in 4–8 weeks with consistent effort
  • Track progress using photos, measurements, and how your clothes fit — not just the scale.
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