Do a calculation. 0.45 kg (1 lb) is about 3500 calories. If you want to lose 0.45 to 0.9 pounds a week (about 1 to 2 pounds), you need to burn about 500 to 1000 calories a day, or exercise more to burn more calories. For example, a 35-year-old woman with moderate physical activity needs to consume about 2000 calories a day to maintain her current weight. You can lose weight as long as your daily calorie intake is reduced to 1400 to 1600. The daily target calorie intake depends on factors such as age, gender and physical activity level. Certain health conditions are also factors to be considered.