How Many Calories You Actually Burn Daily (TDEE Explained)

You've probably heard the simple rule: "to lose weight, eat less than you burn; to gain, eat more than you burn."

That's true. But here's what most people don't know: how many calories you actually burn every day varies wildly based on your body size, age, activity level, and metabolism.

This is where TDEE comes in. Understanding your Total Daily Energy Expenditure (TDEE) is the most powerful tool for reaching any body composition goal.

What is TDEE?

TDEE is the total number of calories your body burns in a day, including:

• Basal Metabolic Rate (BMR): Calories burned at rest just to keep you alive (heart beating, breathing, digestion, brain function, etc.)
• Activity Energy: Calories burned from exercise and daily movement
• Thermic Effect of Food (TEF): Calories burned digesting food (~10% of what you eat)

Add these together, and you get your TDEE.

Understanding BMR (The Base)

Your BMR is the calories you'd burn if you did absolutely nothing—even asleep. It's primarily determined by:

• Body size: Larger bodies burn more calories at rest (more cells to fuel)
• Muscle mass: Muscle tissue burns more calories than fat, even at rest
• Age: Metabolism slows with age (~2-5% per decade after 30)
• Sex: Men typically have higher BMR due to more muscle mass
• Genetics: Some people just have faster or slower metabolisms

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The Mifflin-St Jeor equation is the most accurate widely-available formula for estimating BMR:

Activity Level Multipliers

Your actual TDEE depends heavily on how active you are. Multiply your BMR by your activity level:

• Sedentary (little to no exercise): BMR × 1.2
• Lightly active (1-3 days exercise/week): BMR × 1.375
• Moderately active (3-5 days/week): BMR × 1.55
• Very active (6-7 days/week): BMR × 1.725
• Extremely active (physical job + training): BMR × 1.9

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Example: Sarah's TDEE

Sarah is 28 years old, weighs 150 lbs (68 kg), is 5'6" (168 cm), and works out 4 days a week.

Her BMR: (10 × 68) + (6.25 × 168) − (5 × 28) − 161 = 1,450 calories/day

Her Activity Level: Moderately active (1.55 multiplier)

Her TDEE: 1,450 × 1.55 = 2,247 calories/day

This means Sarah burns approximately 2,250 calories per day. If she eats 2,250 calories, she maintains her weight. If she eats 1,750, she's in a 500-calorie deficit (loses ~1 lb per week). If she eats 2,750, she's in a 500-calorie surplus (gains ~1 lb per week).

Why TDEE Matters More Than BMI

BMI tells you if you're "overweight." TDEE tells you exactly how to change that. It's the difference between knowing you have a problem and knowing exactly how to fix it.

Here's the reality: weight loss isn't complicated. It's simple math. Burn more than you eat, and you lose weight. The TDEE calculation lets you know your personal number.

The Calorie Deficit Rule

• Small deficit (250-300 cal/day): Lose ~0.5 lbs/week. Sustainable, minimal muscle loss
• Moderate deficit (500 cal/day): Lose ~1 lb/week. Effective, manageable
• Large deficit (750+ cal/day): Lose 1.5+ lbs/week. Aggressive, higher muscle loss risk

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Most experts recommend a 300-500 calorie deficit for sustainable fat loss while preserving muscle.

The Calorie Surplus Rule (For Muscle Gain)

• Small surplus (250-300 cal/day): Gain ~0.5 lbs/week. Mostly muscle, minimal fat
• Moderate surplus (500 cal/day): Gain ~1 lb/week. Mix of muscle and fat
• Large surplus (750+ cal/day): Gain 1.5+ lbs/week. Lots of fat gain, not ideal

For muscle gain, aim for a modest surplus combined with strength training. You need the extra calories for muscle growth.

Key Realities About TDEE

It's an Estimate, Not a Prediction

TDEE calculations are estimates based on population averages. Your actual number might be 10-20% higher or lower depending on genetics, metabolism, and unmeasured factors. Use the calculation as a starting point, then adjust based on real results over 2-3 weeks.

It Changes as You Change

Lose 20 lbs, and your TDEE decreases (smaller body = fewer calories burned). Gain muscle, and your TDEE increases (muscle burns more calories). Recalculate monthly if you're making progress.

It's Not Just About Exercise

Total daily movement matters more than gym sessions. A 30-minute workout is ~300 calories. Walking around, fidgeting, occupational activity—these add up. The most active people are usually those with active jobs, not just those who hit the gym.

The Takeaway: Know Your Number

Forget quick weight loss hacks. Forget "eat these superfoods." The real secret to sustainable body composition change is knowing your TDEE and eating appropriately relative to it.

Too low of a deficit? You'll be hungry and quit. Too aggressive? You'll lose muscle and feel terrible. Get the math right, and everything becomes simple.