500 a day is the one-pound-a-week rule
A pound of body fat stores roughly 3,500 calories, so a 500-calorie daily deficit works out to about one pound a week. Your deficit is your TDEE (what you burn in a day) minus what you eat. The 3,500 figure is a useful anchor, but it overstates real loss by 20–30% because the body slows its metabolism as you lose weight.
Deficit to weekly weight loss
| Daily deficit | Per week | Pace |
|---|---|---|
| 250 kcal | ~0.5 lb | Very slow, easy to sustain |
| 500 kcal | ~1.0 lb | The standard CDC target |
| 750 kcal | ~1.5 lb | Moderately aggressive |
| 1,000 kcal | ~2.0 lb | Aggressive; the sensible ceiling |
CDC and NIH both point to 1 to 2 pounds a week as the safe, lasting range. Slower loss tends to hold better.
Where a deficit goes wrong
- Cutting too hard. Above about 1,000 a day you burn more muscle, slow your metabolism further and set up the yo-yo rebound.
- Trusting "calories burned" numbers. Trackers and machines overstate exercise burn by 30–50%. Take most of the deficit from food, a smaller share from movement.
- The scale stalling. Weight swings 1–3 lb a day on water alone. Judge progress on a 7-day average, how clothes fit and body measurements, not one morning.
Common questions
How big a daily deficit loses one pound a week?
About 500 calories a day. A pound of fat holds roughly 3,500 calories, so 500 a day across seven days adds up to that pound. In practice real loss runs a bit slower as the body adapts.
Is a 1,000-calorie deficit safe?
It can be short term, especially if you carry more weight, and gives about two pounds a week. But it raises the risk of muscle loss and fatigue, so most people do better around 500 to 750.
What is the lowest number of calories I should eat?
As a general floor, not below about 1,200 a day for women or 1,500 for men without medical supervision. Eating under that risks nutrient gaps and hormonal problems.
