Calorie Deficit to Lose Weight — How It Works
Weight loss has one non-negotiable rule: consume fewer calories than you burn. Here's exactly how to calculate the right deficit for your goal — without losing muscle or slowing your metabolism.
To lose 1 lb per week, you need a 500 calorie/day deficit (since 3,500 calories ≈ 1 lb of fat). To lose 2 lbs/week, a 1,000 calorie/day deficit is needed — this is generally the maximum safe rate. Going below 1,200 calories/day (women) or 1,500 calories/day (men) is not recommended without medical supervision.
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The Calorie Deficit Formula
Weight loss rate = Calorie Deficit × 7 ÷ 3,500 (lbs per week)
Since 1 lb of fat contains approximately 3,500 calories, a daily deficit of 500 calories will result in about 1 lb of weight loss per week when maintained consistently.
How to Find Your Calorie Deficit Starting Point
- Calculate your TDEE (Total Daily Energy Expenditure)
- Subtract 500 calories for 1 lb/week loss
- Never go below 1,200 cal (women) or 1,500 cal (men)
- Adjust after 2-4 weeks based on actual results
Why Aggressive Deficits Backfire
Very large deficits (1,500+ calories/day) cause muscle loss, metabolic adaptation (your body burns fewer calories), nutritional deficiencies, and rebound weight gain. A moderate deficit of 300-500 cal/day preserves muscle, is easier to sustain, and produces better long-term results.
The Role of Exercise in Your Deficit
Exercise increases TDEE, allowing you to eat more while still maintaining a deficit. Strength training is especially valuable during a cut because it preserves (or builds) muscle even as you lose fat — improving your body composition even at the same scale weight.
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