A calorie deficit means consuming fewer calories than your body burns. One pound of fat = ~3,500 calories. A 500-calorie daily deficit = ~1 pound of fat lost per week. This is the fundamental arithmetic of weight loss — everything else is detail.
Calculate Your Calorie Maintenance Level
How Big Should Your Deficit Be?
- •250 cal/day deficit: 0.5 lb/week — very sustainable, minimal muscle loss, almost no metabolic adaptation
- •500 cal/day deficit: 1 lb/week — standard recommendation, sustainable for most people
- •750 cal/day deficit: 1.5 lb/week — aggressive but manageable, higher hunger and some muscle loss risk
- •1,000+ cal/day deficit: 2+ lb/week — too aggressive for most, significant muscle loss, metabolic adaptation, unsustainable
Two Ways to Create a Deficit
- •Eat less: Easiest to control — tracking calories via MyFitnessPal or Cronometer makes this precise
- •Move more: Adding 30 min of walking burns ~150 extra calories — meaningful but easy to eat back
- •Best results: Combine both — a 300-calorie food reduction + 200 calories of additional activity = 500 cal deficit
The deficit should be from your total daily energy expenditure (TDEE), not just BMR. TDEE accounts for activity. If your TDEE is 2,400 and you eat 1,900, you're in a 500-calorie deficit — regardless of what your app says about "net calories."
Sustainable fat loss = 0.5–1% of body weight per week. For a 200-lb person, that's 1–2 lbs/week. Faster than that and you're losing muscle, water, and setting up a rebound. Slower is almost always better.