Whether you want to build muscle, lose fat, or maintain your current physique, understanding your macronutrients (macros) is essential. In this guide, you'll learn exactly how to calculate your optimal protein, carbs, and fat intake for any fitness goal.
What Are Macros?
Macronutrients are the three main nutrients that provide energy (calories) to your body:
- Protein: 4 calories per gram – builds and repairs muscle tissue
- Carbohydrates: 4 calories per gram – primary energy source for exercise
- Fat: 9 calories per gram – hormone production and nutrient absorption
By manipulating these three macros, you can optimize your nutrition for muscle gain, fat loss, or performance.
Step 1: Calculate Your Daily Calories
Before setting your macros, you need to know your total daily energy expenditure (TDEE). Here's the formula:
Calculate Your BMR (Basal Metabolic Rate)
Use the Mifflin-St Jeor equation:
- 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
Multiply by Activity Level
- Sedentary (desk job): BMR × 1.2
- Lightly active (1-3 days/week): BMR × 1.375
- Moderately active (3-5 days/week): BMR × 1.55
- Very active (6-7 days/week): BMR × 1.725
- Extremely active (athlete): BMR × 1.9
Adjust for Your Goal
- Fat Loss: TDEE - 300 to 500 calories
- Maintenance: TDEE
- Muscle Gain: TDEE + 200 to 400 calories
📱 Skip the Math
Light Weight automatically calculates your calories and macros based on your goals during onboarding. Download the app for instant calculations.
Step 2: Set Your Protein Intake
Protein is the most important macro for body composition. Research shows optimal intakes for different goals:
- Muscle Building: 1.6-2.2g per kg body weight (0.7-1g per lb)
- Fat Loss: 2.0-2.4g per kg body weight (0.9-1.1g per lb)
- Maintenance: 1.4-1.8g per kg body weight (0.6-0.8g per lb)
Example: A 80kg (176 lb) person building muscle: 80 × 2 = 160g protein per day
Step 3: Set Your Fat Intake
Fat is essential for hormone production (including testosterone). Don't go too low!
- Minimum: 0.5g per kg body weight
- Recommended: 0.8-1.2g per kg body weight
- Or: 25-35% of total calories
Example: 80kg person at 1g/kg = 80g fat per day (720 calories from fat)
Step 4: Fill the Rest With Carbs
After protein and fat are set, fill your remaining calories with carbohydrates:
- Calculate calories from protein: Protein (g) × 4
- Calculate calories from fat: Fat (g) × 9
- Subtract from total calories
- Divide by 4 to get carbs in grams
Real-World Examples
Example 1: Male, 80kg, Building Muscle
- TDEE: 2,500 calories
- Goal calories: 2,800 (surplus)
- Protein: 160g (640 cal)
- Fat: 80g (720 cal)
- Carbs: (2800 - 640 - 720) ÷ 4 = 360g
Final Macros: 160P / 360C / 80F
Example 2: Female, 60kg, Fat Loss
- TDEE: 1,800 calories
- Goal calories: 1,400 (deficit)
- Protein: 130g (520 cal)
- Fat: 55g (495 cal)
- Carbs: (1400 - 520 - 495) ÷ 4 = 96g
Final Macros: 130P / 96C / 55F
Track Your Macros Easily
Calculating macros is just the first step—consistently hitting them is what produces results. Use Light Weight to:
- Scan food with AI to instantly log nutrition
- Track daily calories and macros
- Build a personal meal library
- Monitor progress over time