ActiveFit Playbook: How to Calculate Your Calorie Needs Without a Nutritionist

When it comes to fat loss, muscle gain, or simply maintaining your weight, one thing matters above all: energy balance. If you eat more calories than you burn, you gain weight. If you eat fewer, you lose weight. But how do you know how many calories your body needs?

Here’s a simple, step-by-step method you can use today.

Step 1. Calculate Your Basal Metabolic Rate (BMR)

Your BMR is the energy your body needs just to stay alive — breathing, circulating blood, maintaining body temperature.

👉 Use the Mifflin-St Jeor formula (one of the most accurate and practical):

• Men:
  BMR = 10 × weight (kg) + 6.25 × height (cm) – 5 × age (years) + 5
• Women:
  BMR = 10 × weight (kg) + 6.25 × height (cm) – 5 × age (years) – 161

📌 Example:
A 31-year-old man, 179 cm tall, 86 kg:
BMR = (10 × 86) + (6.25 × 179) – (5 × 31) + 5
= 860 + 1119 – 155 + 5
= 1829 calories/day

This is what his body burns at complete rest.

Step 2. Multiply by Your Activity Factor

Next, you calculate your Total Daily Energy Expenditure (TDEE) — the total calories you burn each day, including movement and exercise.

Use this multiplier:

• Sedentary (little/no exercise): ×1.2
• Lightly active (light exercise/sports 1–3 days/week): ×1.375
• Moderately active (moderate exercise 3–5 days/week): ×1.55
• Very active (hard exercise 6–7 days/week): ×1.725
• Extremely active (very hard exercise + physical job): ×1.9

📌 Example (continued):
If the same man trains 5x/week and walks 20,000 steps/day → he’s very active (×1.725).
TDEE = 1829 × 1.725 = 3156 calories/day

This is his maintenance level (where weight stays stable).

Step 3. Adjust for Your Goal

Now that you know your TDEE, adjust it:

• For Fat Loss: subtract 15–25% (e.g., 500–750 calories/day deficit)
• For Muscle Gain: add 10–20% (e.g., 300–500 calories/day surplus)
• For Maintenance: keep calories around TDEE

📌 Example (Fat Loss):
3156 – 500 = ~2650 calories/day

That’s a safe, sustainable deficit for losing fat while maintaining muscle.

Step 4. Track, Test, Adjust

Your calculation is just a starting point. Everyone’s metabolism is slightly different.

👉 Do this:

1. Stick to your calorie target for 2–3 weeks.
2. Track your weight and waist circumference weekly.
3. Adjust by ±150–200 calories if you’re not seeing results.

⚠️ Rule of thumb:

• If you’re not losing ~0.5–1% of bodyweight per week in a fat-loss phase → cut a bit more.
• If you’re not gaining in a surplus → add a bit more.

Step 5. Remember Quality Matters Too

Calories determine whether you lose or gain weight, but macronutrients (protein, carbs, fats) and food quality determine how you look, feel, and perform.

• Protein: ~1.6–2.2 g/kg of bodyweight
• Fats: ~20–30% of total calories
• Carbs: Fill the rest with nutrient-dense carbs for energy

Quick Recap (Action Plan)

1. Calculate your BMR with the Mifflin-St Jeor formula.
2. Multiply by your activity factor to find TDEE.
3. Adjust calories based on your goal.
4. Track progress for 2–3 weeks, then adjust.
5. Focus on macronutrients and food quality, not just calories.

👉 Do this today, and you’ll know exactly how much to eat to move toward your fitness goals — no nutritionist required.