400Calorie Deficit — Weight Loss Rate & Timeline
A daily deficit of 400 calories produces approximately 0.80 lbs/week (3.5 lbs/month) of fat loss, based on the 3,500-calorie-per-pound rule.
Daily Deficit
400 cal
Weekly Loss
0.80 lbs
Monthly Loss
3.5 lbs
Annual Loss (theoretical)
42 lbs
A 400-calorie daily deficit is within the FDA's recommended safe range. At this rate, the body preserves most muscle tissue while losing primarily fat.
To achieve a 400-calorie daily deficit, the typical approach is a combination of dietary reduction (~60–70%) and exercise (~30–40%). For example, reducing food intake by 260 calories and burning 140 via exercise.