Weight loss comes down to one fundamental principle: you must burn more calories than you consume. But how many calories should you actually eat? The answer depends on your body, activity level, and goals.
Step 1 — Calculate Your TDEE
Your Total Daily Energy Expenditure (TDEE) is the total calories your body burns in a day — including exercise, daily movement, and basic metabolism.
TDEE is calculated from your BMR (Basal Metabolic Rate) multiplied by an activity factor:
| Activity Level | Multiplier | Example |
|---|---|---|
| Sedentary | × 1.2 | Desk job, no exercise |
| Lightly Active | × 1.375 | 1-3 workouts/week |
| Moderately Active | × 1.55 | 3-5 workouts/week |
| Very Active | × 1.725 | 6-7 hard workouts/week |
| Extra Active | × 1.9 | Physical job + daily training |
Step 2 — Apply a Calorie Deficit
To lose weight, eat fewer calories than your TDEE. The size of your deficit determines how fast you lose weight:
Daily Calories = TDEE − Deficit
- −250 cal/day = ~0.25 kg (0.5 lb) per week — slow, sustainable
- −500 cal/day = ~0.5 kg (1 lb) per week — standard recommendation
- −750 cal/day = ~0.75 kg (1.5 lb) per week — aggressive
- −1000 cal/day = ~1 kg (2 lb) per week — maximum recommended
⚠️ Never eat below 1,200 calories/day (women) or 1,500 calories/day (men) without medical supervision. Extreme restriction leads to muscle loss, nutrient deficiencies, and metabolic slowdown.
Example Calculation
A 32-year-old woman, 65 kg, 165 cm, moderately active (3-4 workouts/week):
- BMR (Mifflin-St Jeor) = (10 × 65) + (6.25 × 165) − (5 × 32) − 161 = 1,426 kcal
- TDEE = 1,426 × 1.55 = 2,210 kcal/day (maintenance)
- For 0.5 kg/week loss: 2,210 − 500 = 1,710 kcal/day
Macronutrient Breakdown for Weight Loss
Calories matter most, but macros affect body composition and satiety:
- Protein: 30–35% of calories — Preserves muscle during deficit. Aim for 1.6–2.2g per kg of bodyweight.
- Carbohydrates: 35–45% of calories — Fuel for exercise and brain function.
- Fat: 20–30% of calories — Essential for hormones and nutrient absorption.
Beyond Calories: What Else Matters
- Sleep — Poor sleep increases hunger hormones (ghrelin) and reduces satiety hormones (leptin).
- Protein — Highest satiety per calorie. Prevents the muscle loss that slows metabolism.
- Fibre — Slows digestion, keeps you fuller longer. Aim for 25–38g daily.
- Strength training — Builds muscle, which increases TDEE even at rest.
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