It's hard to say. I don't know what constitution you are and how fat you are. Generally, you can lose 5-7 kg after three days. But if you don't control your diet later, the rebound will be very strong. There is no limit to eating apples for three days. As long as you are hungry, you can eat apples. There is another way to lose weight quickly by eating only cucumber eggs a week, and the effect is more obvious, but not many people can persist for seven days. I wish you success in losing weight.