Calorie Calculator

Understanding Daily Calorie Needs

Knowing your daily calorie needs is fundamental for weight management, whether you want to lose, maintain, or gain weight. This calculator uses the Mifflin-St Jeor equation, considered the most accurate for estimating calorie needs, and factors in your activity level to provide total daily energy expenditure (TDEE).

Key Concepts

BMR (Basal Metabolic Rate)

Calories your body burns at complete rest for basic functions: breathing, circulation, cell production, nutrient processing. Represents 60-75% of daily calorie burn.

TDEE (Total Daily Energy Expenditure)

Total calories burned per day including all activities. BMR multiplied by activity factor. This is your maintenance calories.

Calorie Deficit/Surplus

• Deficit: Eat fewer calories than TDEE to lose weight
• Surplus: Eat more calories than TDEE to gain weight
• Maintenance: Eat calories equal to TDEE to maintain weight

Activity Level Guide

• Sedentary (1.2): Office job, minimal exercise
• Light (1.375): Light exercise 1-3 days/week
• Moderate (1.55): Moderate exercise 3-5 days/week
• Active (1.725): Intense exercise 6-7 days/week
• Very Active (1.9): Physical job + intense exercise, or training 2x per day

Weight Loss Guidelines

Safe Weight Loss Rate

• 1-2 pounds per week is safe and sustainable
• Faster loss often leads to muscle loss and rebound weight gain
• 500-calorie daily deficit = 1 lb/week
• 1,000-calorie daily deficit = 2 lbs/week

Minimum Calorie Intake

• Women: Don't go below 1,200 calories/day
• Men: Don't go below 1,500 calories/day
• Very low calorie diets slow metabolism and cause nutrient deficiencies

Macronutrient Distribution

Once you know total calories, divide among macros:

Balanced Diet

• Protein: 25-30% (4 cal/gram)
• Carbs: 40-50% (4 cal/gram)
• Fat: 20-30% (9 cal/gram)

Weight Loss

• Protein: 30-40% (preserves muscle)
• Carbs: 30-40%
• Fat: 20-30%

Muscle Gain

• Protein: 25-35% (0.8-1g per lb body weight)
• Carbs: 40-50% (fuel workouts)
• Fat: 20-30%

Examples

30-year-old Woman, 150 lbs, 5'6", Moderate Activity

• BMR: ~1,425 calories
• TDEE: ~2,210 calories (maintenance)
• Weight loss: ~1,710 calories (-1 lb/week)
• Weight gain: ~2,710 calories (+1 lb/week)

35-year-old Man, 180 lbs, 5'10", Light Activity

• BMR: ~1,785 calories
• TDEE: ~2,455 calories (maintenance)
• Weight loss: ~1,955 calories (-1 lb/week)
• Weight gain: ~2,955 calories (+1 lb/week)

Tracking Tips

1. Use apps: MyFitnessPal, Lose It, Cronometer
2. Food scale: Weigh portions for accuracy
3. Read labels: Check serving sizes carefully
4. Track everything: Include drinks, snacks, condiments
5. Plan meals: Prep in advance to hit targets
6. Adjust weekly: Modify based on results

Why Calorie Counting May Not Work

• Inaccurate tracking: Underestimating portions is common
• Metabolism adaptation: Body adjusts to reduced calories
• Water weight: Masks fat loss on scale
• Muscle gain: Adds weight while losing fat
• Hormones: Thyroid, cortisol, insulin affect weight
• Sleep/stress: Poor sleep and stress hinder weight loss

Beyond Calories

While calories matter, food quality is crucial:

• 100 calories of broccoli ≠ 100 calories of candy
• Whole foods provide nutrients, fiber, satiety
• Processed foods spike blood sugar, increase hunger
• Protein and fiber keep you full longer
• Focus on nutrient density, not just calorie count

Plateaus and Adjustments

If weight loss stalls after 2-3 weeks:

1. Reduce calories by 100-200
2. Increase exercise intensity or duration
3. Adjust macros (more protein, fewer carbs)
4. Check for hidden calories (oils, sauces)
5. Ensure adequate sleep (7-9 hours)
6. Manage stress (cortisol affects weight)