Calculate Your Daily Calorie Needs

Activity Level Guide

Basal Metabolic Rate (BMR): 60-75% of TDEE

BMR is the largest component of TDEE, representing calories burned for essential physiological functions: breathing, circulation, cell production, nutrient processing, protein synthesis, and ion transport. BMR occurs even during complete rest or sleep. It's determined primarily by lean body mass—muscle tissue burns ~6 calories/pound/day vs. ~2 calories/pound/day for fat. This is why muscular individuals have higher BMRs than those with higher body fat percentages at identical weights. BMR decreases approximately 1-2% per decade after age 30, primarily from muscle loss.

Thermic Effect of Food (TEF): ~10% of TDEE

TEF represents calories burned digesting, absorbing, and processing nutrients. Different macronutrients have different thermic effects: protein requires 20-30% of its calories for processing (highest TEF), carbohydrates 5-10%, and fats only 0-3%. A high-protein diet (30% protein) increases daily calorie burn by 50-100 calories compared to high-fat diet through elevated TEF. This is one reason high-protein diets are effective for fat loss—they naturally increase energy expenditure while also improving satiety and preserving muscle during calorie restriction.

Exercise Activity Thermogenesis (EAT): 5-10% of TDEE

EAT encompasses calories burned during planned, structured exercise: gym workouts, running, cycling, sports, etc. While exercise is crucial for health, cardiovascular fitness, and muscle building, it typically contributes relatively little to total daily calorie burn for most people. A 45-minute moderate-intensity workout might burn 300-500 calories—significant but only 15-20% of a 2,500-calorie TDEE. This is why "you can't out-exercise a bad diet"—creating calorie deficits through diet is more efficient than through exercise alone, though combining both produces best results.

Non-Exercise Activity Thermogenesis (NEAT): 15-30% of TDEE

NEAT is often the most variable and underestimated TDEE component, representing all movement that isn't formal exercise: walking to the car, climbing stairs, fidgeting, occupational activities, household chores, typing, standing, and even maintaining posture. NEAT can vary by 2,000+ calories daily between individuals with identical stats—a construction worker burns vastly more NEAT calories than an office worker. Increasing NEAT through standing desks, taking stairs, parking farther away, pacing while on phone calls, and general movement throughout the day can significantly impact TDEE without requiring gym time. This is why "active lifestyle" matters as much as structured exercise.

Step 1: Calculate BMR (Mifflin-St Jeor Equation)

Step 2: Multiply BMR by Activity Factor

Maintaining Current Weight

To maintain weight, consume calories equal to your TDEE. This balances energy intake with expenditure, keeping body weight stable. However, perfect precision isn't necessary—staying within ±100-200 calories of TDEE still maintains weight due to day-to-day metabolic fluctuations. Daily weight varies 2-5 pounds from water retention, food volume, sodium intake, and hormones, so track weekly averages rather than daily weigh-ins. If weight trends up or down over 2-3 weeks despite eating at calculated TDEE, adjust calories by 100-200 in the appropriate direction.

Fat Loss: Creating a Calorie Deficit

For fat loss, eat below your TDEE. A 500 cal/day deficit produces ~0.5 kg (1 lb) weekly loss; a 1,000 cal/day deficit targets ~1 kg (2 lbs) weekly. For a 2,500 TDEE: eat 2,000 cal/day for 1 lb/week loss or 1,500 cal/day for 2 lbs/week loss. Moderate deficits (500-750 cal) are sustainable long-term with minimal muscle loss, reduced hunger, and preserved metabolic rate. Aggressive deficits (1,000+ cal) accelerate fat loss but increase muscle loss risk, metabolic adaptation, hunger, and adherence challenges. Never eat below 1,200 cal/day (women) or 1,500 cal/day (men) without medical supervision—this risks nutrient deficiencies, muscle loss, and metabolic damage.

Muscle Gain: Creating a Calorie Surplus

For muscle building, eat above your TDEE. A 250-500 cal/day surplus supports lean muscle gain when combined with progressive resistance training (~0.25-0.5 kg weekly gain). Larger surpluses accelerate weight gain but increase fat accumulation disproportionately—muscle synthesis has biological limits. For 2,500 TDEE: eat 2,750-3,000 cal/day for lean bulking. Without strength training, surplus calories become predominantly fat. Prioritize protein (1.6-2.2 g/kg bodyweight) to optimize muscle protein synthesis. Gaining too slowly (<0.25 kg/month) indicates insufficient surplus; gaining too quickly (>1 kg/month) suggests excessive fat gain requiring calorie reduction.