Calorie Deficit Guide: How to Calculate TDEE, Safe Deficits & Lose Weight
A calorie deficit occurs when you consume fewer calories than you burn. Learn to calculate your TDEE, set a safe daily deficit, and understand why 3,500 calories ≈ 1 lb of fat.
How to Calculate Your TDEE
Total Daily Energy Expenditure (TDEE) is the total calories your body burns in 24 hours, accounting for both baseline metabolism and physical activity. It's calculated by multiplying your Basal Metabolic Rate (BMR) by an activity multiplier. The Mifflin-St Jeor equation is the most validated BMR formula for the general US adult population, preferre
Setting the Right Calorie Deficit
A 500 calorie/day deficit is the classic recommendation for ~1 lb/week fat loss, based on the approximation that 3,500 calories ≈ 1 lb of body fat. In reality, weight loss rate varies by individual, and very large deficits lead to muscle loss, metabolic adaptation, and poor adherence. Evidence-based deficit guidelines by goal: Slow/sustainable loss
The 3,500-Calorie Rule (and Its Limits)
The rule that 3,500 calories equals 1 pound of body fat comes from the caloric density of pure adipose tissue. In practice, early weight loss often exceeds predictions because of water weight reduction, while later phases slow as metabolism adapts. A more accurate model (the NIH Body Weight Planner) accounts for metabolic adaptation: for every 10 c
Macronutrient Targets for a Deficit Diet
Calorie quantity matters most for weight loss, but macronutrient composition affects body composition, satiety, and muscle retention. High protein intake (0.7–1.0 g per lb of body weight) is particularly critical during a calorie deficit to preserve lean mass. General macro targets for a fat loss phase: Protein 30–35% of calories. Fat 25–35% of cal
Frequently Asked Questions
How many calories should I eat to lose 1 pound per week?
Eat approximately 500 calories below your TDEE each day to lose ~1 lb/week. Example: if your TDEE is 2,400 calories, eat 1,900 calories/day. Track for 2–3 weeks and adjust based on actual results — TDEE estimates have ±10–15% individual variation.
Is a 1,000 calorie per day deficit safe?
A 1,000 cal/day deficit (targeting ~2 lb/week loss) is generally safe for people with a higher starting weight and a TDEE above 2,500 calories, where it represents less than 40% of total expenditure. For smaller individuals, this deficit is too aggressive and risks muscle loss, f
Why am I not losing weight in a calorie deficit?
The most common reasons are: (1) inaccurate calorie tracking — most people underestimate intake by 20–40%; (2) metabolic adaptation — TDEE has dropped with weight loss; (3) water retention masking fat loss, especially with new exercise. Audit your tracking, recalculate TDEE at cu
Should I eat back calories burned from exercise?
Partially, yes. Fitness trackers overestimate calorie burn by 30–40% on average. A practical approach: eat back 50% of estimated exercise calories. For example, if a 45-minute run shows 400 calories burned, add 200 calories to your daily target. This maintains the deficit while f
What is the minimum safe calorie intake per day?
Most nutrition guidelines recommend a minimum of 1,200 calories/day for women and 1,500 calories/day for men to avoid nutritional deficiencies and muscle loss. Below these levels, diet should be medically supervised. For context, most moderately active adults have TDEEs of 1,800–