How many calories should I eat to lose weight?
Subtract 250–1,000 calories from your TDEE. A 500 cal deficit produces ~1 lb/week loss. Never go below 1,200 cal/day (women) or 1,500 cal/day (men) without medical supervision.
What is TDEE and why does it matter?
TDEE (Total Daily Energy Expenditure) is the total calories you burn per day, including your BMR plus activity. Eating below your TDEE creates a deficit; eating above creates a surplus.
Which BMR formula is most accurate?
Mifflin-St Jeor is validated as the most accurate for most adults (±10%). Katch-McArdle is more accurate if you know your body fat %. Harris-Benedict is a well-known classic but slightly less accurate for modern populations.
How does the adaptive thermogenesis model work?
The body reduces its metabolic rate in response to sustained calorie restriction. This calculator models an ~8% reduction after 8 weeks and ~15% after 16 weeks, showing a realistic "adaptive" weight loss curve alongside the idealized linear projection.
How much protein should I eat on a cut?
Aim for 0.8–1.2g per lb of goal body weight (1.6–2.6g/kg). Higher protein preserves muscle mass and increases satiety. This calculator targets 1g/lb of goal weight as a practical default.
Is a 1,000 calorie deficit safe?
A 1,000 cal/day deficit (theoretical 2 lbs/week) is the maximum generally recommended. It risks muscle loss, nutrient deficiency, and rapid metabolic adaptation. Most people do better at 500–750 cal/day.
Why is my weight loss slower than the calculator predicted?
Metabolic adaptation, water retention, reduced non-exercise activity (NEAT), and inaccurate food logging are the most common causes. Recalculate your TDEE every 10–15 lbs lost and consider a 1–2 week diet break every 8–12 weeks.
What is Katch-McArdle and when should I use it?
Katch-McArdle calculates BMR from lean mass (total weight × (1 - body fat %)) rather than total body weight. It's most accurate for lean or muscular individuals whose total weight would overestimate fat mass.
Should I lose weight faster or slower?
Slower is almost always better for muscle preservation. Losing 0.5–1% of body weight per week minimizes muscle loss. For a 185 lb person, that's under 1.85 lbs/week — roughly a 500–650 cal deficit.
How do I calculate macros while in a calorie deficit?
Protein first (1g/lb goal weight), then fat (25% of calories ÷ 9g/kcal), then carbs fill the remainder. This calculator generates a starting macro split automatically.
Will I lose muscle on a calorie deficit?
Some muscle loss is inevitable, but it's minimized by: adequate protein (≥1g/lb), strength training 3×/week, moderate deficit size (≤750 cal/day), and avoiding very low calorie diets.
What should I do when weight loss plateaus?
After 2+ weeks of no change: (1) verify accurate food logging, (2) subtract 100–150 cal, (3) add 20–30 min daily walking, (4) take a 1-week diet break at maintenance, or (5) recalculate TDEE at your new weight.
Does meal frequency affect fat loss?
Total daily calories and protein drive fat loss — meal frequency has minimal impact. Eat 3–6 meals based on what helps you stay consistent, feel satisfied, and hit your protein targets.
How does activity level affect my calorie target?
Activity multipliers range from 1.2 (sedentary, desk job, no exercise) to 1.9 (athlete training twice daily). Choosing the wrong multiplier is the #1 source of error — when in doubt, start at "Light Active" and adjust based on 2-week results.
How accurate is this calculator?
TDEE estimates are ±10–15% for most people. Use results as a starting point, track actual weight change for 2 weeks, then adjust by 100–200 cal if not losing at the expected rate. Real-world accuracy improves with precise food logging.