To lose one pound of body weight, it is generally estimated that you need to create a calorie deficit of about 3,500 calories. This means burning 3,500 more calories than you consume, either by eating less, increasing physical activity, or a combination of both

. A common practical approach is to reduce your daily calorie intake by 500 calories, which would theoretically result in losing about one pound per week (500 calories/day × 7 days = 3,500 calories)

. However, this is a simplified rule and actual weight loss can vary due to factors such as body composition, metabolism changes, gender, age, and activity level

. Recent research has shown that the 3,500-calorie rule tends to overestimate weight loss and does not account for the body's adaptive responses to dieting, which slow down metabolism and reduce calorie needs as you lose weight

. Therefore, weight loss may be slower than predicted, and maintaining a calorie deficit over the long term is key. In summary:

• About 3,500 calories equals roughly 1 pound of body fat.
• A daily deficit of 500 calories can lead to approximately 1 pound of weight loss per week.
• Individual results vary, and weight loss often slows over time due to metabolic adaptations.
• Sustainable changes in diet and activity are essential for long-term weight loss success

This means that while the 3,500-calorie deficit is a useful guideline, it should be used with realistic expectations and combined with lifestyle changes for best results.