Calorie Calculator

A calorie calculator determines how many calories you need to consume daily to maintain, lose, or gain weight. It's based on your Basal Metabolic Rate (BMR) - the calories your body burns at rest - and your physical activity level.

Understanding your caloric needs is fundamental to achieving and maintaining a healthy weight sustainably, without extreme diets or dangerous restrictions.

Key Concepts

• BMR (Basal Metabolic Rate): Calories you burn just existing (breathing, blood circulation, cellular functions)
• TDEE (Total Daily Energy Expenditure): Total calories you burn including physical activity
• Caloric deficit: Consuming fewer calories than you burn to lose weight
• Caloric surplus: Consuming more calories than you burn to gain weight

What is it for?

This calculator is essential for:

• Weight control - Lose, maintain, or gain weight healthily
• Nutritional planning - Design balanced diets
• Fitness and sports - Optimize performance and recovery
• General health - Avoid nutritional deficiencies or excesses
• Specific goals - Competitions, pregnancy, recovery

Required Data

1. Gender - Men and women have different BMRs
2. Age - Metabolism decreases with age
3. Weight - In kilograms or pounds
4. Height - In centimeters or feet/inches
5. Activity level:
   • Sedentary (little or no exercise)
   • Light (exercise 1-3 days/week)
   • Moderate (exercise 3-5 days/week)
   • Intense (exercise 6-7 days/week)
   • Very intense (exercise 2x daily, athletes)

Formulas Used

Mifflin-St Jeor Equation (most accurate):

• 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

TDEE = BMR × Activity Multiplier

Multipliers:

• Sedentary: 1.2
• Light: 1.375
• Moderate: 1.55
• Intense: 1.725
• Very intense: 1.9

Situation: Maria is 32 years old, 165 cm tall, weighs 75 kg, and exercises moderately (3-4 days/week). She wants to lose weight healthily. How many calories should she consume?

Step 1: Calculate BMR

• BMR = (10 × 75) + (6.25 × 165) - (5 × 32) - 161
• BMR = 750 + 1,031.25 - 160 - 161
• BMR = 1,460.25 calories/day

Step 2: Calculate TDEE

• TDEE = BMR × Moderate activity multiplier
• TDEE = 1,460.25 × 1.55
• TDEE = 2,263 calories/day

Step 3: Caloric Deficit for Weight Loss

• Recommended deficit: 10-20% (moderate and sustainable)
• 15% deficit = 2,263 × 0.15 = 339 calories
• Target calories = 2,263 - 339 = 1,924 calories/day

Result:

• Maria should consume approximately 1,900-2,000 calories daily
• Expected weight loss: 0.5 kg per week (healthy and sustainable)
• In 3 months: approximately 6 kg loss

✅ Don't go below 1,200 calories (women) or 1,500 (men): Too few calories slow metabolism and cause nutritional deficiencies.

✅ Moderate deficit is sustainable: Losing 0.5-1 kg per week is healthy. Faster losses are usually unsustainable and harmful.

✅ Quality over quantity: 1,500 calories of nutritious foods are better than 1,500 of junk food.

✅ Adjust based on results: If after 2-3 weeks you see no changes, reduce calories by 100-200 per day.

✅ Track everything you eat: Using apps like MyFitnessPal helps you be honest about your real intake.

✅ Exercise counts, but don't overestimate it: It's easy to overvalue calories burned in exercise. Be conservative.

Are all calories equal?

No. 100 calories of broccoli don't affect your body the same as 100 calories of cookies. Nutrients, fiber, and how hormones process each food matter. Focus on whole, nutritious foods.

Do I need to count calories forever?

Not necessarily. Counting calories is an educational tool. Over time, you develop intuition about portions and needs. Many people count only when establishing new goals.

Why am I not losing weight if I'm in a deficit?

Possible reasons: (1) You underestimate consumed calories, (2) You overestimate burned calories, (3) Temporary water retention, (4) Muscle gain offsetting fat loss, (5) You need more time (2-3 weeks to see real changes).

Does it matter when I eat the calories?

Less than you think. What matters most is the daily total. That said, distributing meals can help with satiety and energy. Find what works for you.

How many calories does exercise burn?

It varies enormously:

• Walking (5 km/h): ~200-300 cal/hour
• Running (8 km/h): ~500-700 cal/hour
• Weights: ~200-400 cal/hour
• Intense cycling: ~600-900 cal/hour

Does metabolism get "damaged" by diets?

Metabolism does adapt (slightly decreases) with prolonged caloric restriction, but it doesn't permanently "break." Taking breaks (maintenance weeks) can help.