Calorie calculator
Your body burns calories just existing. A 180-lb person burns roughly 1,800 calories/day doing nothing — that's your Basal Metabolic Rate (BMR). Add daily activities and you get Total Daily Energy Expenditure (TDEE). The average American eats 3,600 calories/day, nearly double their TDEE. The gap becomes stored fat at roughly 3,500 calories per pound.
Good to know
"Eating less, moving more" is technically correct but unhelpful. A 500-calorie deficit can come from eating 500 fewer calories, burning 500 more, or a combination. But exercise burns fewer calories than people think: running a mile burns about 100 calories. You can't outrun a bad diet. Most successful weight loss is primarily dietary.
Metabolism doesn't "break," but it does adapt. Extended calorie restriction reduces BMR by 5-15% as the body conserves energy. This "metabolic adaptation" is why weight loss plateaus occur. Periodic diet breaks (eating at maintenance) can help reset adaptation. Extreme restriction causes more adaptation than moderate deficits.
Protein has a thermic advantage. Your body burns 20-30% of protein calories just digesting them, compared to 5-10% for carbs and 0-3% for fats. A high-protein diet (1g per lb body weight) effectively lowers caloric intake and preserves muscle during weight loss. This is why protein-focused diets work better than calorie-counting alone.
Disclaimers & sources
For reference only. Not medical or dietary advice. Consult a healthcare provider for weight or nutrition plans.