Macros — short for macronutrients — are the three main components of food that provide calories: protein, carbohydrates, and fat. Calculating your macros means figuring out exactly how many grams of each to eat daily to reach your specific goal, whether that's losing fat, building muscle, or maintaining your weight.
Step 1: Calculate Your TDEE
Before you can set macro targets, you need to know your Total Daily Energy Expenditure (TDEE) — how many calories your body burns each day.
Find Your BMR
Your Basal Metabolic Rate (BMR) is the calories you burn at rest. Use the Mifflin-St Jeor equation:
Men:
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women:
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Multiply by Activity Level
| Activity Level | Multiplier | Description |
|---|---|---|
| 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 |
| Extra active | 1.9 | Very hard exercise + physical job |
TDEE = BMR × Activity Multiplier
Example: A 30-year-old woman, 65 kg, 168 cm tall, moderately active:
- BMR = (10 × 65) + (6.25 × 168) − (5 × 30) − 161 = 650 + 1050 − 150 − 161 = 1,389 calories
- TDEE = 1,389 × 1.55 = 2,153 calories/day
Step 2: Set Your Calorie Target
Adjust your TDEE based on your goal:
| Goal | Adjustment | Rate |
|---|---|---|
| Fat loss | −300 to −500 cal/day | 0.3–0.5 kg/week loss |
| Aggressive cut | −500 to −750 cal/day | 0.5–0.75 kg/week |
| Maintenance | TDEE ± 0–100 cal | Maintain weight |
| Muscle gain (lean bulk) | +200 to +300 cal/day | 0.1–0.2 kg/week gain |
| Aggressive bulk | +300 to +500 cal/day | 0.2–0.4 kg/week |
Our example woman (fat loss): TDEE 2,153 − 400 = 1,753 calories/day target
Step 3: Set Your Protein Target
Protein is the most important macro for body composition. It preserves muscle during a cut and supports muscle growth during a bulk.
General guidelines:
- Fat loss: 1.8–2.2 g per kg of body weight
- Muscle gain: 1.6–2.2 g per kg of body weight
- Maintenance: 1.4–1.8 g per kg
- Higher end if training intensely or older (35+)
Example: 65 kg woman, fat loss goal → 2.0 g/kg
Protein = 65 × 2.0 = 130 g protein/day
Calories from protein = 130 × 4 = 520 calories
(Protein provides 4 calories per gram)
Step 4: Set Your Fat Target
Fat supports hormones, brain function, and absorption of fat-soluble vitamins. Don't go too low.
Minimum: 0.7 g per kg body weight (don't go below this) Recommended: 0.8–1.2 g per kg for most people
Example: 65 kg woman → 0.9 g/kg
Fat = 65 × 0.9 = 58.5 g fat/day → round to 60 g
Calories from fat = 60 × 9 = 540 calories
(Fat provides 9 calories per gram)
Step 5: Fill Remaining Calories with Carbs
Carbohydrates fill the rest of your calorie budget. They fuel workouts and support performance.
Remaining calories = Total target − (protein calories + fat calories)
Carb grams = Remaining calories ÷ 4
Example:
Remaining = 1,753 − 520 − 540 = 693 calories
Carbs = 693 ÷ 4 = 173 g carbs/day
Final Macro Split Example
| Macro | Grams | Calories | % of Total |
|---|---|---|---|
| Protein | 130 g | 520 cal | 30% |
| Fat | 60 g | 540 cal | 31% |
| Carbs | 173 g | 692 cal | 39% |
| Total | 1,752 cal | 100% |
Common Macro Splits by Goal
| Goal | Protein | Fat | Carbs |
|---|---|---|---|
| Fat loss | 30–35% | 25–30% | 35–45% |
| Muscle gain | 25–30% | 20–25% | 45–55% |
| Maintenance | 20–30% | 25–35% | 40–50% |
| Keto | 20–25% | 65–75% | 5–10% |
| Endurance athlete | 15–20% | 20–25% | 55–65% |
How to Track Macros
Apps: MyFitnessPal, Cronometer, and MacroFactor make tracking straightforward — scan barcodes or search their databases.
Food scales: Measuring in grams is far more accurate than cups or spoons, especially for calorie-dense foods like nuts, oils, and cheese.
Consistency beats perfection: Hitting within ±10g on protein and ±15–20g on carbs and fat is close enough. Don't let perfect be the enemy of good.
Do You Need to Track Every Day Forever?
No. Most people track consistently for 4–8 weeks, build an intuitive sense of what's in common foods, then track loosely or only during periods where they've drifted from their goals.
Tips for Hitting Your Protein Target
Getting 130–160 g of protein daily is the biggest challenge for most people. Prioritise:
- Chicken breast (31g/100g)
- Greek yogurt (10g/100g)
- Cottage cheese (11g/100g)
- Eggs (6g per egg)
- Tuna in water (26g/100g)
- Lean beef (26g/100g)
- Protein powder (20–25g per scoop) — use as supplement, not primary source
Common Mistakes
Setting protein too low — This is the most common error. Inadequate protein makes fat loss harder and muscle gain slower.
Going too low in calories — A deficit larger than 750 cal/day increases muscle loss, decreases energy, and is rarely sustainable.
Ignoring fat minimums — Very low fat diets can impair hormone production, particularly testosterone and oestrogen.
Changing everything at once — Adjust calories first for 2–3 weeks, then fine-tune macros based on progress.